Purine derivatives as A3 adenosine receptor-selective agonists

ABSTRACT

Disclosed are (N)-methanocarba adenine nucleosides, e.g., of formula (I) as highly potent A 3  adenosine receptor agonists, pharmaceutical compositions comprising such nucleosides, and a method of use of these nucleosides, wherein R 1 -R 6  are as defined in the specification. These nucleosides exhibit similar selectivities as agonists of the A 3  versus the A 1  receptor for both human and mouse adenosine receptors, and are contemplated for use in the treatment a number of diseases, for example, inflammation, cardiac ischemia, stroke, asthma, diabetes, and cardiac arrhythmias.

CROSS-REFERENCE TO A RELATED APPLICATION

This application claims the benefit of U.S. Provisional Patent Application No. 61/040,985, filed Mar. 31, 2008, the disclosure of which is incorporated by reference.

BACKGROUND OF THE INVENTION

Extracellular adenosine acts as a local modulator at four subtypes of adenosine receptors, namely, A₁, A_(2A), A_(2B), and A₃, which are involved in numerous physiological and pathophysiological processes. Fredholm et al., Pharmacol. Rev. 2001; 53:527-52. For example, adenosine attenuates the effects of ischemia in the heart and brain. Acting through the A_(2A) adenosine receptor, it suppresses prolonged inflammation; Ohta et al., Nature 2001; 414:916-920; and causes vasodilation and inhibits platelet aggregation, thus increasing the amount of oxygen available to an organ under stress. Adenosine agonists selective for the A₃ adenosine receptor are of interest as cerebroprotective, cardioprotective, and anticancer agents. von Lubitz et al., Eur. J. Pharmacol., 1994, 263:59-67; Liu et al., Cardiovasc Res., 1994, 28:1057-61; Strickler et al., J. Clin. Invest., 1996, 98:1773-9; Fishman et al., Oncogene, 2004, 23:2465-71.

The potential utility of A₁ and A₂-selective agents in therapeutic applications has been limited by accompanying side effects, given the ubiquitous nature of the A₁ and A₂ receptors. The distribution of the A₃ adenosine receptor, by contrast, is fairly limited, being found primarily in the CNS, brain, testes, and immune system, where it appears to be involved in the modulation of release from mast cells of mediators of the immediate hypersensitivity reaction (Ramkumar et al., J. Biol. Chem., 268, 16887-16890 (1993)). The limited distribution of the A₃ adenosine receptor provides a basis for predicting that A₃-selective compounds may be more useful than A₁- and A₂-selective compounds as potential therapeutic agents.

Accordingly, there is a great interest for finding A₃ adenosine receptor agonists, as shown by the patenting activity in this area; see, for example, U.S. Pat. Nos. 5,773,423 and 5,688,774; and U.S. Published Patent Application No. 2003/0216412 A1. Therefore, there is a desire for A₃ adenosine receptor agonists, especially those that are selective to A₃ adenosine receptor over the A₁ and A₂ adenosine receptors.

BRIEF SUMMARY OF THE INVENTION

The invention provides A₃ selective agonists, particularly N-methanocarba adenine nucleosides, for example, with selected substituents at the 2, N⁶, 2′,3′,4′, and/or 5′-positions, pharmaceutical compositions comprising such nucleosides, and methods of use thereof, for example, in a method for selectively activating an A₃ adenosine receptor of a mammal comprising administering to the mammal an effective amount of a nucleoside of the invention. Compounds of the invention exhibit similar selectivities as agonists of the A₃ versus the A₁ receptor which are species-independent.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 depicts a reaction scheme for the synthesis of compounds 3 and 4 in accordance with an embodiment of the invention. Reagents and conditions: (a) 3-chlorobenzylamine; (b) MeNH₂, EtOH; (c) Me₃SiC≡CH, PdCl₂(PPh₃)₂, CuI, DMF, Et₃N; (d) TFA, MeOH, H₂O; (e) n-Bu₄NF, THF.

FIG. 2 depicts a reaction scheme for the synthesis of compounds 26, 10, and 11 in accordance with an embodiment of the invention. Reagents and conditions: (f) 3-iodobenzylamine; (g) MeNH₂, EtOH; (h) HC≡C(CH₂)₃COOCH₃, CuI, DMF, Et₃N; (i) TFA, MeOH, H₂O; (j) H₂NCH₂CH₂NH₂; (k) Ac₂O.

FIG. 3 depicts a reaction scheme for the synthesis of compounds 37 to 41 in accordance with an embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is predicated on the concept that adenosine analogues having a ring constraint and optionally having large lipophilic substituents at the C-2 and/or N⁶-positions would display high selectivity as agonists of the A₃ adenosine receptor versus the A₁ and A_(2A) adenosine receptors for both human and mouse and/or rat adenosine receptors.

Accordingly, the present invention provides compounds of Formula (1):

wherein:

R¹ is selected from the group consisting of C₁-C₆ alkyl, C₁-C₆ alkoxy, hydroxyl, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkyl C₁-C₆ alkyl, C₃-C₈ dicycloalkyl C₁-C₆ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₆ alkyl, C₇-C₁₄ tricycloalkyl C₁-C₆ alkyl, C₆-C₁₄ aryl, C₆-C₁₄ aryl C₁-C₆ alkyl, C₆-C₁₄ diaryl C₁-C₆ alkyl, C₆-C₁₄ aryl C₁-C₆ alkoxy, heterocyclyl C₁-C₆ alkyl, heterocyclyl, 4-[[[4-[[[(2-amino C₁-C₆ alkyl)amino]-carbonyl]-C₁-C₆ alkyl]aniline]carbonyl]C₁-C₆ alkyl]C₆-C₁₄ aryl, and C₆-C₁₄ aryl C₃-C₈ cycloalkyl, wherein the aryl or heterocyclyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, hydroxyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₁-C₆ alkoxy, C₆-C₁₄ aryloxy, hydroxy C₁-C₆ alkyl, hydroxy C₂-C₆ alkenyl, hydroxy C₂-C₆ alkynyl, carboxy C₁-C₆ alkyl, carboxy C₂-C₆ alkenyl, carboxy C₂-C₆ alkynyl, aminocarbonyl C₁-C₆ alkyl, aminocarbonyl C₂-C₆ alkenyl, aminocarbonyl C₂-C₆ alkynyl, and any combination thereof, and the alkyl or cycloalkyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, alkyl, alkoxy, aryloxy, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, aminocarbonylalkoxy, and arylalkoxy, and any combination thereof;

R² is selected from the group consisting of iodo, C₁-C₂₀ alkyl, C₇-C₁₂ cycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkenyl C₁-C₂₀ alkyl, C₆-C₁₄ aryl C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkenyl, C₆-C₁₄ aryl C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₁-C₂₀ alkyl C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, C₆-C₁₄ aryl C₂-C₂₀ alkynyl, and the alkyl, cycloalkyl, or aryl portion of R² is optionally substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, sulfur, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof; or R² is selected from the group consisting of amino (alkylamino)_(n) alkylaminocarbonyl wherein n is 1 to 6, aminoalkylcarbonylaminoalkylaminocarbonyl, aminoalkylaminocarbonyl whose amino end is linked to a label, amino (alkylamino)_(n) alkylaminocarbonyl wherein n is 1 to 6 whose amino end is linked to a label, and aminoalkylcarbonylaminoalkylaminocarbonyl whose amino end is linked to a label;

R³ and R⁴ are independently selected from the group consisting of hydroxyl, amino, thiol, ureido, C₁-C₆ alkyl carbonylamino, hydroxy C₁-C₆ alkyl, and hydrazinyl; and

R⁵ is selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl) aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, hydrazinyl, amino C₁-C₃ alkyl, hydroxy C₁-C₃ alkyl, C₃-C₆ cycloalkylamino, hydroxylamino, and C₂-C₃ alkenyl;

or a pharmaceutically acceptable salt thereof, with the proviso that when R² is iodo, R³ and

R⁴ are hydroxyl, and R⁵ is methylaminocarbonyl, R¹ is not 3-chlorobenzyl.

The term “aryl” refers to aromatic moieties such as phenyl, naphthyl, anthracenyl, and biphenyl. The term “heterocyclyl” refers to 3-7 membered rings which can be saturated or unsaturated, comprising carbon and one or more heteroatoms such as O, N, and S, and optionally hydrogen; optionally in combination with one or more aromatic rings. Examples of heterocyclyl groups include pyridyl, piperidinyl, piperazinyl, pyrazinyl, pyrolyl, pyranyl, tetrahydropyranyl, tetrahydrothiopyranyl, pyrrolidinyl, furanyl, tetrahydrofuranyl, thiophenyl, tetrahydrothiophenyl, purinyl, pyrimidinyl, thiazolyl, thiazolidinyl, thiazolinyl, oxazolyl, tetrazolyl, tetrazinyl, benzoxazolyl, morpholinyl, thiophorpholinyl, quinolinyl, and isoquinolinyl.

The alkyl, alkoxy, and alkylamino groups can be linear or branched. When an aryl group is substituted with a substituent, e.g., halo, amino, alkyl, hydroxyl, alkoxy, and others, the aromatic ring hydrogen is replaced with the substituent and this can take place in any of the available hydrogens, e.g., 2, 3, 4, 5, and/or 6-position wherein the 1-position is the point of attachment of the aryl group in the compound of the present invention.

The term “halo” refers to fluorine, chlorine, bromine, and iodine. Examples of bicycloalkyls include norbornyl, s-endonorbornyl, carbamethylcylopentyl, and bicyclohexyl. An example of a tricycloalkyl is adamantyl.

When a group is substituted with sulfur, a hydrogen atom of the group is replaced with a sulfur atom or an oxidized sulfur atom. The sulfur atom may be monosubstituted with an alkyl or aryl group to form a thiol group, or may be disubstituted with alkyl and/or aryl groups to form a thioether group. When the sulfur atom is oxidized, the oxidized sulfur atom is a part of sulfoxide group or a sulfone group.

In an embodiment, R¹ is selected from the group consisting of C₁-C₆ alkyl, C₃-C₈ cycloalkyl, C₆-C₁₄ aryl C₁-C₆ alkyl, C₆-C₁₄ diaryl C₁-C₆ alkyl, C₆-C₁₄ aryl C₃-C₈ cycloalkyl, and heterocyclyl C₁-C₆ alkyl, wherein the aryl or heterocyclyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, C₁-C₆ alkyl, C₁-C₆ alkoxy, C₆-C₁₄ aryloxy, hydroxy C₁-C₆ alkyl, hydroxy C₂-C₆ alkenyl, hydroxy C₂-C₆ alkynyl, aminocarbonyl C₁-C₆ alkoxy, and C₆-C₁₄ aryl C₁-C₆ alkoxy, and any combination thereof. Preferably, R¹ is selected from the group consisting of methyl, cyclopentyl, benzyl, diphenylethyl, phenyl cyclopropyl, diphenyl cyclopropyl, and 2,2-diphenylethyl, wherein the phenyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, hydroxyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, C₁-C₆ alkyl, C₁-C₆ alkoxy, phenoxy, hydroxy C₁-C₆ alkyl, hydroxy C₂-C₆ alkenyl, hydroxy C₂-C₆ alkynyl, and any combination thereof. In a specific embodiment, R¹ is benzyl.

In another embodiment, R¹ is methyl. In a further embodiment, R¹ is cyclopentyl or 7-norbornyl. Other embodiments include those wherein R¹ is trans-2-phenyl-1-cyclopropyl or 2,2-diphenylethyl.

A specific example of R¹ is benzyl substituted with one or more substituents selected from the group consisting of halo, amino, methyl, methoxy, phenoxy, hydroxymethyl, hydroxypropynyl, carboxypropynyl, alkoxycarbonylpropynyl, aminocarbonyl methoxy, and benzyloxy, and any combination thereof. When the benzyl group is monosubstituted, the substitution can be at the 2-, 3-, or 4-position of the benzyl group, and is preferably at the 3-position of the benzyl group. Specific examples of substituted benzyl groups are 3-chlorobenzyl, 3-bromobenzyl, 3-iodobenzyl, 3-(3-hydroxypropynyl)benzyl, and 2,5-dimethoxybenzyl.

In any of the embodiments discussed above, R² is preferably selected from the group consisting of iodo, C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, and C₆-C₁₄ aryl C₂-C₂₀ alkynyl. More preferably, R² is C₂-C₂₀ alkynyl. Optionally, R² is substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, sulfur, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof. alkynyl. More preferably, R² is C₂-C₂₀ alkynyl. Optionally, R² is substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, sulfur, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof. More preferably, R² is substituted with one or more substituents selected from the group consisting of amino, alkylamino, dialkylamino, carboxy, alkoxycarbonyl, aminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof.

In any of the embodiments discussed above, R³ and R⁴ are preferably independently selected from the group consisting of hydroxyl, amino, mercapto (i.e., SH), and ureido, and more preferably R³ and R⁴ are hydroxyl.

In any of the embodiments discussed above, R⁵ is preferably selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl) aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, amino C₁-C₃ alkyl, hydroxy C₁-C₃ alkyl, and C₃-C₆ cycloalkylamino, more preferably R⁵ is C₁-C₃ alkyl aminocarbonyl or di(C₁-C₃ alkyl) aminocarbonyl, and even more preferably R⁵ is methylaminocarbonyl.

Specific examples of the compounds of the invention are compounds wherein R¹ is 3-chlorobenzyl, R³ and R⁴ are hydroxyl, and R⁵ is methylamino carbonyl, and R² is ethynyl, 2-trimethylsilylethynyl, 1-pentynyl, 5-carbomethoxy-1-pentynyl, 5-carboxy-1-pentynyl, 5-(2-aminoethyl)aminocarbonyl-1-pentynyl, or iodo; and R¹ is 2,5-dimethoxybenzyl, R² is iodo, R³ and R⁴ are hydroxyl, and R⁵ is methylaminocarbonyl.

In accordance with an embodiment, the invention provides a compound of formula I, wherein R² is selected from the group consisting of carboxyalkylalkynyl, alkoxycarbonylalkylalkynyl, aminoalkylaminocarbonylalkyl alkynyl, amino (alkylamino)_(n) alkylaminocarbonyl wherein n is 1 to 6, aminoalkylcarbonylaminoalkylaminocarbonyl, aminoalkylaminocarbonyl whose amino end is linked to a label, dye, or reporter group, amino (alkylamino)_(n) alkylaminocarbonyl wherein n is 1 to 6 whose amino end is linked to a label, dye, or reporter group, aminoalkylcarbonylaminoalkylaminocarbonyl whose amino end is linked to a label, dye, or reporter group, for example, a dye, particularly a fluorescent dye. The label can be a radioactive group such as ¹²⁵I.

In a particular embodiment, the invention provides a compound of formula I, wherein R¹ is 3-chlorobenzyl, R² is selected from the group consisting of C≡—C(CH₂)₂COOH, C≡C(CH₂)₄COOH, C≡C(CH₂)₂COOCH₃, C≡C(CH₂)₄COOCH₃,

R³ and R⁴ are hydroxyl, and R⁵ is methylamino carbonyl, or a pharmaceutically acceptable salt thereof.

A specific example of a compound of formula I, wherein R¹ is 3-chlorobenzyl and R² is C≡C(CH₂)₂CONH(CH₂)₂NH—CO—(CH₂)₅Cy5 is compound 44.

Among the N⁶-3-chlorobenzyl, 5′-N-methylamide substituted compounds of the invention, the 2-ethynyl, N⁶-3-chlorobenzyl analog 3 displayed K_(i) values at the human and mouse A₃ adenosine receptors of 1.30 nM and 0.85 nM, respectively, while exhibiting selectivities for the A₃ versus the A₁ adenosine receptors of 134 for human and 53.6 for mouse. Other N⁶-3-chlorobenzyl analog analogues such as the 2-(2-trimethylsilylethynyl) derivative 4, the 2-(1-pentynyl) derivative 5, the 2-(5-methoxycarbonyl-1-pentynyl) derivative 6, the 2-(5-carboxy-1-pentynyl) derivative 7, and the 2-(5-(2-aminoethyl)aminocarbonyl-1-pentynyl) derivative 8 all exhibited K_(i) values at the human A₃ adenosine receptor of about 2 nM or less, with a selectivity for the human A₃ adenosine receptor versus the A₁ adenosine receptor of 160 to 6260, while exhibiting K_(i) values at the mouse A₃ adenosine receptor of about 8.7 nM or less, with a selectivity for the mouse A₃ adenosine receptor versus the mouse A₁ adenosine receptor of 35.6 to 229. Thus, the ratio of A₃ to A₁ adenosine receptor selectivities for human as compared to mouse adenosine receptors observed for 2-alkynyl, N⁶-3-chlorobenzyl analogs of the invention ranged from about 1.4 to 5.7. The 2-iodo, N⁶-3-chlorobenzyl derivative 1 and the 2-iodo, 2,5-dimethoxybenzyl derivative 2 exhibited K_(i) values at the human A₃ adenosine receptor of 3.6 nM and 1.3, respectively, with A₃/A₁ adenosine receptor selectivities of 610 and 2360, respectively, while the ratio of A₃/A₁ adenosine receptor selectivities observed in human versus mouse adenosine receptors was 12.1 and 3.4, respectively. Compounds 12, 13, 14, 17-20, 31, 37, and 40 exhibited K_(i) values at the human A₃ AR of about 2 nM or less with selectivities up to about 1900 for the human A₃ AR vs the human A₁ AR.

By way of contrast, the 2-chloro, N⁶-3-chlorobenzyl analog 13 exhibited A₃/A₁ adenosine receptor selectivity for human adenosine receptors that was 87 times greater than observed with mouse adenosine receptors, and exhibited only a 10.3-fold selectivity for A₃ versus A₁ adenosine receptors for mouse adenosine receptors.

The compounds of formula I provide an advantage that functionalized congeners can be prepared from these compounds. For example, starting from the amine or carboxyl end of R², various moieties can be attached covalently. Thus, for example, carriers can be covalently attached for enhancing drug delivery. Dendrimers, e.g., PAMAM polyamine dendrimers, such as G3 dendrimers, can be covalently attached to provide multivalent binding. Reporter groups or moieties can be attached for probing distal interactions with adenosine receptors. Spectroscopic probes such as fluorescent probes, ESR probes, or NMR probes can be covalently linked to the amine or carboxyl ends. Other pharmacophores may be covalently linked to the amine or carboxyl ends so that dual acting drugs can be produced, example, an A₁ AR agonist can be linked to an A₃ AR agonist or a P2Y₁, P2Y₂, P2Y₄, P2Y₆, or P2Y₁₁ agonist, an M1 receptor antagonist, or an A₁ AR antagonist can be linked to an A₃ AR agonist. The amine or carboxyl ends could also be covalently linked to amino acids, peptides, nucleic acids, glycosides, and one or more small molecules. Examples of other probes include opioid receptor probes. Examples of fluorescent probes are BODIPY and FITC. Cy3B is another example of a cyanine dye.

The present invention also provides compounds of the formula:

wherein:

R⁶ is C₆-C₁₄ aryl C₁-C₆ alkyl wherein the C₆-C₁₄ aryl is substituted with a group represented by C≡C—(CH₂)_(n)—COR¹¹ wherein R¹ is selected from the group consisting of OH, OR¹², NR¹³R¹⁴, wherein R¹² is selected from the group consisting of C₁-C₆ alkyl, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkyl C₁-C₆ alkyl, C₃-C₈ dicycloalkyl C₁-C₆ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₆ alkyl, C₇-C₁₄ tricycloalkyl C₁-C₆ alkyl, C₆-C₁₄ aryl, C₆-C₁₄ aryl C₁-C₆ alkyl, C₆-C₁₄ diaryl C₁-C₆ alkyl;

R¹³ and R¹⁴ are independently selected from the group consisting of hydrogen, C₁-C₆ alkyl, and (CH₂)_(n)R¹⁵ wherein R¹⁵ is NR¹⁶ _(R) ¹⁷, wherein R¹⁶ and R¹⁷ are independently selected from the group consisting of hydrogen, C₁-C₆ alkyl, and COR¹⁸ wherein R¹⁸ is hydrogen or C₁-C₆ alkyl; wherein n is an integer from 1 to 10;

R⁷ is selected from the group consisting of bromo, chloro, iodo, C₁-C₂₀ alkyl, C₇-C₁₂ cycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkenyl C₁-C₂₀ alkyl, C₆-C₁₄ aryl C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkenyl, C₆-C₁₄ aryl C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, C₆-C₁₄ aryl C₂-C₂₀ alkynyl, and the alkyl, cycloalkyl, or aryl portion of R⁷ is optionally substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, sulfur, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof;

R⁸ and R⁹ are independently selected from the group consisting of hydroxyl, amino, thiol, ureido, C₁-C₆ alkyl carbonylamino, hydroxy C₁-C₆ alkyl, and hydrazinyl; and

R¹⁰ is selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl) aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, hydrazinyl, amino C₁-C₃ alkyl, hydroxy C₁-C₃ alkyl, C₃-C₆ cycloalkylamino, hydroxylamino, and C₂-C₃ alkenyl; or a pharmaceutically acceptable salt thereof, with the proviso that when R⁷ is chloro, R⁸ and R⁹ are hydroxyl, and R¹⁰ is methylaminocarbonyl, R⁶ is not 3-(3-hydroxypropynyl)benzyl.

In a further embodiment, R⁶ is benzyl substituted with C≡C—(CH₂)_(n)—COR¹¹, wherein n is as defined herein. Preferably, R¹¹ is selected from the group consisting of OH, OR¹², and NR¹³R¹⁴. When R¹¹ is OR¹², preferably R¹² is C₁-C₆ alkyl.

In another embodiment, R¹¹ is NR¹³R¹⁴. In a further embodiment, R¹³ and R¹⁴ are both hydrogen. In another embodiment R¹³ is hydrogen and R¹⁴ is (CH₂)_(n)R¹⁵ wherein R¹⁵ is NR¹⁶R¹⁷, wherein R¹⁶ and R¹⁷ are independently selected from the group consisting of hydrogen, C₁-C₆ alkyl, and COR¹⁸ wherein R¹⁸ is hydrogen or C₁-C₆ alkyl, and wherein n is defined herein.

In any of the embodiments of Formula II, R⁷ is preferably selected from the group consisting of chloro, bromo, iodo, C₁-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₁-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₁-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₁-C₂₀ alkynyl, and C₆-C₁₄ aryl C₁-C₂₀ alkynyl. More preferably, R⁷ is selected from the group consisting of chloro, bromo, and iodo.

In any of the embodiments of Formula II, R⁸ and R⁹ are preferably independently selected from the group consisting of hydroxyl, amino, thiol, and ureido, and more preferably R⁸ and R⁹ are hydroxyl.

In any of the embodiments of Formula II, R¹⁰ is preferably selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl) aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, amino C₁-C₃ alkyl, hydroxy C₁-C₃ alkyl, and C₃-C₆ cycloalkylamino, more preferably R¹⁰ is C₁-C₃ alkyl aminocarbonyl or di(C₁-C₃ alkyl) aminocarbonyl, and even more preferably R¹⁰ is methylaminocarbonyl.

Specific examples of the compounds of the invention as represented by Formula II are compounds wherein R⁶ is 3-(5-carboxy-1-pentynyl), R⁷ is chloro, R⁸ and R⁹ are hydroxyl, and R¹⁰ is methylamino carbonyl; R⁶ is 3-(5-(2-aminoethyl)aminocarbonyl-1-pentynyl), R⁷ is chloro, R⁸ and R⁹ are hydroxyl, and R¹⁰ is methylamino carbonyl; and R⁶ is 3-(5-(2-acetamidoethyl)aminocarbonyl-1-pentynyl), R⁷ is chloro, R⁸ and R⁹ are hydroxyl, and R¹⁰ is methylamino carbonyl.

Among the 2-chloro, 5′-N-methylamide substituted compounds of the invention, the N⁶-3-(3-hydroxy-1-propynyl)benzyl derivative 16, the N⁶-3-(5-carboxy-1-pentynyl)benzyl derivative 9, N⁶-3-(5-(2-aminoethyl)aminocarbonyl-1-pentynyl)benzyl derivative 10, and the N⁶-3-(5-(2-acetamidoethyl)aminocarbonyl-1-pentynyl)benzyl derivative 11 exhibited K_(i) values at the human A₃ adenosine receptor of 2.9 nM, 17.1 nM, 5.21 nM, and 2.88 nM, respectively, with a selectivity for the human A₃ adenosine receptor versus the A₁ adenosine receptor of 900, 19, 52, and 63, respectively, while exhibiting K_(i) values at the mouse A₃ adenosine receptor of 1.94 nM to 14.4 nM. The ratio of A₃ to A₁ adenosine receptor selectivities for human as compared mouse adenosine receptors observed for 2-chloro, N⁶-substituted benzyl compounds of the invention were 0.4 to 15.7. All of the inventive compounds were only weakly active at either human or mouse A₂ adenosine receptors. This is compared with the 2-chloro, N⁶-3-chlorobenzyl analog 13 already discussed herein, which exhibited considerably lower A₃ to A₁ adenosine receptor selectivity with mouse adenosine receptors and a substantially lower A₃ to A₁ adenosine receptor selectivity for mouse adenosine receptors as compared to human adenosine receptors.

The compounds of the present invention can be prepared by any suitable method. For example, intermediates 22-25 can be prepared by the method of Tchilibon et al., J. Med. Chem., 2005, 48, 1745-1758. (1′S,2′R,3′S,4′S,5′S)-4′-[6-Chloro-2-iodo-purin-9-yl]-2′,3′-isopropylidene-bicyclo[3.1.0]hexane-1′-carboxylic acid ethyl ester (22) is reacted with primary amines to introduce R¹ at the N⁶ position of the purine residue via displacement of chloride. Subsequent amination of the 5′ ester group generates an N-alkylamide (e.g., N-methylamide) at the 5′ position. Sonogashira alkynylation at the C-2 position introduces R² wherein R² is alkynyl. Hydrolysis of the isopropylidine group provides target compounds having R²=alkynyl.

(1′S,2′R,3′S,4′S,5′S)-4′-[2,6-Dichloro-purin-9-yl]-2′,3′-isopropylidene-bicyclo[3.1.0]hexane-1′-carboxylic acid methyl ester (24) reactes with 3-iodobenzylamine to introduce a 3-iodobenzylamino group at the N⁶ position of the purine residue via displacement of chloride. Subsequent amination of the 5′ ester group generates an N-alkylamide (e.g., N-methylamide) at the 5′ position. Sonogashira alkynylation at the 3-position of the phenyl ring followed by hydrolysis of the isopropylidine group provides target compounds having 3-alkynylated benzylamino groups at N⁶.

Preparation of aminocarbonylalkynyl derivatives proceeds via (a) Sonogashira coupling using alkoxycarbonylalkynes, followed by aminolysis with diaminoethane, to give amides. 2-(Aminoethyl)aminocarbonylalkyne 10 is acylated with, e.g., acetic anhydride, to provide (2-acetamidoethyl)aminocarbonylalkynyl derivative 11. Compounds 31-44 can be prepared following the reaction scheme described in FIG. 3.

The present invention further provides a pharmaceutical composition comprising a compound as described above and a pharmaceutically acceptable carrier. The present invention provides a pharmaceutical composition comprising a pharmaceutically acceptable carrier and an effective amount, e.g., a therapeutically effective amount, including a prophylactically effective amount, of one or more of the aforesaid compounds, or salts thereof, of the present invention.

Examples of pharmaceutically acceptable salts for use in the present inventive pharmaceutical composition include those derived from mineral acids, such as hydrochloric, hydrobromic, phosphoric, metaphosphoric, nitric and sulphuric acids, and organic acids, such as tartaric, acetic, citric, malic, lactic, fumaric, benzoic, glycolic, gluconic, succinic, maleic and arylsulfonic, for example, benzenesulfonic and p-toluenesulfonic, acids.

The pharmaceutically acceptable carrier can be any of those conventionally used and is limited only by chemico-physical considerations, such as solubility and lack of reactivity with the compound, and by the route of administration. It will be appreciated by one of skill in the art that, in addition to the following described pharmaceutical compositions; the compounds of the present invention can be formulated as inclusion complexes, such as cyclodextrin inclusion complexes, or liposomes.

The pharmaceutically acceptable carriers described herein, for example, vehicles, adjuvants, excipients, or diluents, are well known to those who are skilled in the art and are readily available to the public. It is preferred that the pharmaceutically acceptable carrier be one which is chemically inert to the active compounds and one which has no detrimental side effects or toxicity under the conditions of use.

The choice of carrier will be determined in part by the particular active agent, as well as by the particular method used to administer the composition. Accordingly, there is a wide variety of suitable formulations of the pharmaceutical composition of the present invention. The following formulations for oral, aerosol, parenteral, subcutaneous, intravenous, intraarterial, intramuscular, interperitoneal, intrathecal, rectal, and vaginal administration are merely exemplary and are in no way limiting.

Formulations suitable for oral administration can consist of (a) liquid solutions, such as an effective amount of the compound dissolved in diluents, such as water, saline, or orange juice; (b) capsules, sachets, tablets, lozenges, and troches, each containing a predetermined amount of the active ingredient, as solids or granules; (c) powders; (d) suspensions in an appropriate liquid; and (e) suitable emulsions. Liquid formulations may include diluents, such as water and alcohols, for example, ethanol, benzyl alcohol, and the polyethylene alcohols, either with or without the addition of a pharmaceutically acceptable surfactant, suspending agent, or emulsifying agent. Capsule forms can be of the ordinary hard- or soft-shelled gelatin type containing, for example, surfactants, lubricants, and inert fillers, such as lactose, sucrose, calcium phosphate, and cornstarch. Tablet forms can include one or more of lactose, sucrose, mannitol, corn starch, potato starch, alginic acid, microcrystalline cellulose, acacia, gelatin, guar gum, colloidal silicon dioxide, croscarmellose sodium, talc, magnesium stearate, calcium stearate, zinc stearate, stearic acid, and other excipients, colorants, diluents, buffering agents, disintegrating agents, moistening agents, preservatives, flavoring agents, and pharmacologically compatible carriers. Lozenge forms can comprise the active ingredient in a flavor, usually sucrose and acacia or tragacanth, as well as pastilles comprising the active ingredient in an inert base, such as gelatin and glycerin, or sucrose and acacia, emulsions, gels, and the like containing, in addition to the active ingredient, such carriers as are known in the art.

The compounds of the present invention, alone or in combination with other suitable components, can be made into aerosol formulations to be administered via inhalation. These aerosol formulations can be placed into pressurized acceptable propellants, such as dichlorodifluoromethane, propane, nitrogen, and the like. They also may be formulated as pharmaceuticals for non-pressured preparations, such as in a nebulizer or an atomizer.

Formulations suitable for parenteral administration include aqueous and non-aqueous, isotonic sterile injection solutions, which can contain anti-oxidants, buffers, bacteriostats, and solutes that render the formulation isotonic with the blood of the intended recipient, and aqueous and non-aqueous sterile suspensions that can include suspending agents, solubilizers, thickening agents, stabilizers, and preservatives. The compound can be administered in a physiologically acceptable diluent in a pharmaceutical carrier, such as a sterile liquid or mixture of liquids, including water, saline, aqueous dextrose and related sugar solutions, an alcohol, such as ethanol, isopropanol, or hexadecyl alcohol, glycols, such as propylene glycol or polyethylene glycol, glycerol ketals, such as 2,2-dimethyl-1,3-dioxolane-4-methanol, ethers, such as poly(ethyleneglycol) 400, an oil, a fatty acid, a fatty acid ester or glyceride, or an acetylated fatty acid glyceride with or without the addition of a pharmaceutically acceptable surfactant, such as a soap or a detergent, suspending agent, such as pectin, carbomers, methylcellulose, hydroxypropylmethylcellulose, or carboxymethylcellulose, or emulsifying agents and other pharmaceutical adjuvants.

Oils, which can be used in parenteral formulations include petroleum, animal, vegetable, or synthetic oils. Specific examples of oils include peanut, soybean, sesame, cottonseed, corn, olive, petrolatum, and mineral. Suitable fatty acids for use in parenteral formulations include oleic acid, stearic acid, and isostearic acid. Ethyl oleate and isopropyl myristate are examples of suitable fatty acid esters. Suitable soaps for use in parenteral formulations include fatty alkali metal, ammonium, and triethanolamine salts, and suitable detergents include (a) cationic detergents such as, for example, dimethyl dialkyl ammonium halides, and alkyl pyridinium halides, (b) anionic detergents such as, for example, alkyl, aryl, and olefin sulfonates, alkyl, olefin, ether, and monoglyceride sulfates, and sulfosuccinates, (c) nonionic detergents such as, for example, fatty amine oxides, fatty acid alkanolamides, and polyoxyethylene-polypropylene copolymers, (d) amphoteric detergents such as, for example, alkyl-beta-aminopropionates, and 2-alkyl-imidazoline quaternary ammonium salts, and (3) mixtures thereof.

The parenteral formulations will typically contain from about 0.5 to about 25% by weight of the active ingredient in solution. Suitable preservatives and buffers can be used in such formulations. In order to minimize or eliminate irritation at the site of injection, such compositions may contain one or more nonionic surfactants having a hydrophile-lipophile balance (HLB) of from about 12 to about 17. The quantity of surfactant in such formulations ranges from about 5 to about 15% by weight. Suitable surfactants include polyethylene sorbitan fatty acid esters, such as sorbitan monooleate and the high molecular weight adducts of ethylene oxide with a hydrophobic base, formed by the condensation of propylene oxide with propylene glycol. The parenteral formulations can be presented in unit-dose or multi-dose sealed containers, such as ampoules and vials, and can be stored in a freeze-dried (lyophilized) condition requiring only the addition of the sterile liquid carrier, for example, water, for injections, immediately prior to use. Extemporaneous injection solutions and suspensions can be prepared from sterile powders, granules, and tablets of the kind previously described.

The compounds of the present invention may be made into injectable formulations. The requirements for effective pharmaceutical carriers for injectable compositions are well known to those of ordinary skill in the art. See Pharmaceutics and Pharmacy Practice, J. B. Lippincott Co., Philadelphia, Pa., Banker and Chalmers, eds., pages 238-250 (1982), and ASHP Handbook on Injectable Drugs, Toissel, 4th ed., pages 622-630 (1986).

Additionally, the compounds of the present invention may be made into suppositories by mixing with a variety of bases, such as emulsifying bases or water-soluble bases. Formulations suitable for vaginal administration may be presented as pessaries, tampons, creams, gels, pastes, foams, or spray formulas containing, in addition to the active ingredient, such carriers as are known in the art to be appropriate.

The present invention provides a method for activating A₃ adenosine receptors in a cell comprising contacting the cell with an effective amount of one or more of the inventive compounds or a pharmaceutically acceptable salt thereof. The contacting can be in vitro or in vivo. When the contacting is done in vitro, the contacting can be done by any suitable method, many of which are known in the art. For example, the cell can be provided in a culture medium and the inventive compound introduced into the culture medium per se, or as a solution of the compound in an appropriate solvent.

The present invention provides a method of selectively activating A₃ adenosine receptors in a mammal, which method comprises administering to a mammal in need of selective activation of its A₃ adenosine receptors a therapeutically effective amount, including a prophylactically effective amount, of one or more of the inventive compounds or a pharmaceutically acceptable salt(s) thereof which binds with the A₃ receptor so as to stimulate an A₃ receptor-dependent response. The compound can be administered acutely or chronically.

The mammal can be any suitable mammal and typically is a human, a mouse, or a rat. Desirably, the inventive compounds exhibit A₃/A₁ adenosine receptor selectivity that is less than about 10:1 when determined using human and mouse adenosine receptors.

The method of the present invention has particular usefulness in in vivo applications. For example, A₃ adenosine receptor agonists can be used in the treatment of any disease state or condition involving the release of inositol-1,4,5-triphosphate (IP3), diacylglycerol (DAG), and free radicals and subsequent arachidonic acid cascades. Thus, high blood pressure, locomotor hyperactivity, hypertension, acute hypoxia, depression, and infertility can be treated in accordance with the present inventive method, wherein one of the above-described compounds is acutely administered, e.g., within about a few minutes to about an hour of the onset or realization of symptoms. The method also has utility in the treatment of chronic disease states and conditions, in particular those conditions and disease states wherein chronic prophylactic or therapeutic administration of one of the above-described compounds will prevent the onset of symptoms or will reduce recovery time. Examples of disease states and conditions that may be chronically treated in accordance with the present inventive method include inflammatory disorders, such as vascular inflammation and arthritis, allergies, asthma, wound healing, stroke, cardiac failure, acute spinal cord injury, acute head injury or trauma, seizure, neonatal hypoxia (cerebral palsy; prophylactic treatment involves chronic exposure through placental circulation), chronic hypoxia due to arteriovenous malformations and occlusive cerebral artery disease, ischemia and reperfusion injury in skeletal muscle, severe neurological disorders related to excitotoxicity, Parkinson's disease, Huntington's chorea, and other diseases of the CNS, cardiac disease, kidney disease, and contraception.

The following examples further illustrate the invention but, of course, should not be construed as in any way limiting its scope.

Example 1

¹H NMR spectra were obtained with a Varian Gemini 300 spectrometer using CDCl₃, DMSO-d₆, and CD₃OD as solvents. Chemical shifts are expressed in δ values (ppm). TLC analysis was carried out on aluminum sheets precoated with silica gel F₂₅₄ (0.2 mm) from Sigma-Aldrich. Low-resolution mass spectrometry was performed with a JEOL™ SX102 spectrometer with 6-kV Xe atoms following desorption from a glycerol matrix or on an AGILENT™ LC/MS 1100 MSD, with a WATERS™ (Milford, Mass.) ATLANTIS™ C18 column. Flash chromatography was performed using silica gel (200-400 mesh, 60 Å, Sigma-Aldrich). High resolution mass spectroscopic (HRMS) measurements were performed on a proteomics optimized Q-TOF-2 (MICROMASS-WATERS™) using external calibration with polyalanine. Observed mass accuracies are those expected based on known performance of the instrument as well as trends in masses of standard compounds observed at intervals during the series of measurements. Reported masses are observed masses uncorrected for this time-dependent drift in mass accuracy.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-Chloro-2-iodo-purin-9-yl]-2′,3′-isopropylidene-bicyclo[3.1.0]hexane-1′-carboxylic acid ethyl ester (22), (1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-iodopurin-9-yl]-2′,3′-O-isopropylidene bicyclo[3.1.0]hexane-1′-carboxylic N-methylamide (23), (1′S,2′R,3′S,4′S,5′S)-4′-[2,6-Dichloro-purin-9-yl]-2′,3′-isopropylidene-bicyclo[3.1.0]hexane-1′-carboxylic acid methyl ester (24), and (1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Iodobenzylamino)-2-iodopurin-9-yl]-2′,3′-O-isopropylidene bicyclo[3.1.0]hexane-1′-carboxylic N-methylamide (25) were prepared according to a published method. Tchilibon et al., J. Med. Chem., 2005, 48, 1745-1758.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(2,5-Dimethoxybenzylamino)-2-iodopurin-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (2). To a solution of compound 22 (49 mg, 0.1 mmol) in dichloromethane (0.1 mL) was added 2,5-dimethoxybenzylamine (167 mg, 1 mmol). The reaction mixture was left for 16 h at 22° C., transferred to a chromatographic column, and eluted with 30% to 50% ethyl acetate-hexane to afford the corresponding 6-(2,5-dimethoxybenzyl) derivative. The product was dissolved in a 33% solution of methylamine in ethanol and left at room temperature for 48 h. The reaction mixture was evaporated, and the residue was purified by flash chromatography (50% to 100% ethyl acetate-hexane) to afford the corresponding N-methylamide. The product was dissolved in MeOH (3 mL), and TFA (0.3 mL), and water (3 mL) were added, and the reaction mixture was stirred for 16 h at 70° C. The reaction mixture was evaporated, and the residue was purified by flash chromatography (0 to 10% methanol-ethyl acetate) to afford the title compound 2 (10 mg, 21%). ¹H NMR (CD₃OD) 7.94 (s, 1H), 6.98 (d, 1H, J=2.7 Hz), 6.89 (d, 1H, J=9.3 Hz), 6.78 (dd, 1H, J=2.7, 9.0 Hz), 5.09 (d, 1H, J=7.2 Hz), 4.78 (s, 1H), 4.57 (br s, 2H), 3.98 (d, 1H, J=6.6 Hz), 2.88 (s, 3H), 2.01 (m, 1H), 1.78 (t, 1H, J=4.8 Hz), 1.33 (m, 1H). HRMS (ESI MS m/z) Calcd. for C₂₂H₂₅IN₆O₅ (M+H)+ 581.10039, found 581.0955.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-Methoxyamino-2-chloropurin-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (21). To a solution of compound 24 (20 mg, 0.033 mmol) in dichloromethane (0.1 mL) was added a solution of O-methylhydroxylamine hydrochloride (84 mg, 1 mmol) and triethylamine (101 mg, 1 mmol) in ethanol (0.5 mL). The reaction mixture was left for 16 h at 22° C., diluted with ethyl acetate (30 mL), washed with water, dried, and evaporated. The residue was dissolved in 33% solution of methylamine in ethanol and stirred at room temperature for 48 h. The reaction mixture was evaporated, and the residue was purified by flash chromatography (50% to 100% ethyl acetate-hexane) to afford the corresponding N-methylamide. The product was dissolved in MeOH (3 mL), and TFA (0.3 mL) and water (3 mL) were added. The reaction mixture was stirred for 16 h at 70° C. The reaction mixture was evaporated, and the residue was purified by flash chromatography (0% to 10% methanol-ethyl acetate) to afford the title compound 21 (1.5 mg, 8.5%). ¹H NMR (CD₃OD): 7.45 (s, 1H), 5.07 (d, 1H, J=6.3 Hz), 4.63 (s. 1H), 4.04 (d, 1H, J=6.6 Hz), 3.80 (s, 3H) 2.78 (s, 3H), 2.04 (m, 1H), 1.72 (m, 1H), 1.31 (m, 1H). HRMS (ESI MS m/z) Calcd for C₁₄H₁₆ClN₆O₄ ⁻ (M−H⁺) 367.0927, found 367.0930.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-trimethylsilylethynyl-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (4). To a solution of (1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-chlorobenzylamino)-2-iodopurin-9-yl]-2′,3′-O-isopropylidene bicyclo[3.1.0]hexane-1′-carboxylic N-methylamide 23, 30 mg, 0.05 mmol), dichlorobis(triphenylphosphine)palladium(II) (7 mg, 0.01 mmol), and in DMF (0.05 mL) under nitrogen was added trimethylsilylacetylene (20 mg, 0.20 mmol) and then triethylamine (101 mg, 0.5 mmol). The reaction was stirred at room temperature for 16 h, diluted with ethyl acetate, washed with water, dried, and evaporated. The residue was purified by flash chromatography (30% to 100% ethyl acetate-hexane) to afford the corresponding 2-trimethylsilylethynyl derivative. The product was dissolved in MeOH (3 mL), TFA (0.3 mL) and water (3 mL) were added, and the reaction mixture was stirred for 16 h at 70° C. The reaction mixture was evaporated, and the residue was purified by flash chromatography (0 to 10% methanol-ethyl acetate) to afford the title compound 4 (38%). ¹H NMR (CD₃OD): 8.10 (s, 1H), 7.42 (s, 1H), 7.28 (m, 3H), 4.96 (d, 1H, J=6.6 Hz), 4.7-4.9 (br. m. 3H), 3.97 (d, 1H, J=6.6 Hz) 2.84 (s, 3H), 2.09 (m, 1H), 1.86 (t, 1H, J=5.1 Hz), 1.36 (m, 1H), 0.27 (s, 9H). HRMS (ESI MS m/z) Calcd for C₂₅H₃₀ClN₆O₃Si⁺ (M+H)⁺ 525.1832, found 525.1837.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(1-pentynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (5). To a solution of (1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-chlorobenzylamino)-2-iodopurin-9-yl]-2′,3′-O-isopropylidene bicyclo[3.1.0]hexane-1′-carboxylic N-methylamide (23) (30 mg, 0.05 mmol), dichlorobis(triphenylphosphine)palladium(II) (7 mg, 0.01 mmol), and CuI (1 mg, 0.005 mmol) in DMF (0.05 mL) under nitrogen was added 1-pentyne (14 mg, 0.20 mmol) and then triethylamine (101 mg, 0.5 mmol). The reaction was stirred at room temperature for 16 h, diluted with ethyl acetate, washed with water, dried, and evaporated. The residue was purified by flash chromatography (30% to 100% ethyl acetate-hexane) to afford the corresponding 2-(1-pentynyl) derivative. The product was dissolved in MeOH (3 mL), TFA (0.3 mL) and water (3 mL) were added, and the reaction mixture was stirred for 16 h at 70° C. The reaction mixture was evaporated, and the residue was purified by flash chromatography (0% to 10% methanol-ethyl acetate) to afford the title compound 5. Yield 51%. ¹H NMR (CD₃OD): 8.06 (s., 1H), 7.41 (s, 1H), 7.23-7.30 (m, 3H), 4.99 (d, 1H, J=5.7 Hz), 4.80 (br. s, 3H), 3.96 (d, 1H, J=6.6 Hz), 2.84 (s, 3H), 2.42 (t, 2H, J=7.2 Hz), 2.07 (m, 1H), 1.84 (t, 1H, J=4.5 Hz), 1.65 (sextet, 2H, J=7.2 Hz), 1.36 (m, 1H). HRMS (ESI MS m/z) Calcd for C₂₅H₂₈ClN₆O₃ ⁺ (M+H)⁺ 495.1906, found 495.1911.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(5-methoxycarbonyl-1-pentynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (6) and (1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-chlorobenzylamino)-2-(5-hydroxycarbonyl-1-pentynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (7). To a solution of (1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-chlorobenzylamino)-2-iodopurin-9-yl]-2′,3′-O-isopropylidenebicyclo[3.1.0]hexane-1′-carboxylic N-methylamide (23) (30 mg, 0.05 mmol), dichlorobis(triphenylphosphine)palladium(II) (7 mg, 0.01 mmol), and CuI (1 mg, 0.005 mmol) in DMF (0.05 mL) under nitrogen was added methyl co-hexynoate (26 mg, 0.20 mmol) and then triethylamine (101 mg, 0.5 mmol). The reaction was stirred at room temperature for 16 h, diluted with ethyl acetate, washed with water, dried, and evaporated. The residue was purified by flash chromatography (30% to 100% ethyl acetate-hexane) to afford the corresponding 2-(5-methoxycarbonylpentyn-1-yl) derivative. The product was dissolved in MeOH (3 mL), TFA (0.3 mL) and water (3 mL) were added, and the reaction mixture was stirred for 16 h at 70° C. The reaction mixture was evaporated, and the residue was purified by flash chromatography (0% to 10% methanol-ethyl acetate) to afford the title compound 6 (31%). ¹H NMR (CD₃OD): 7.98 (s, 1H), 7.31 (s, 1H), 7.15-7.31 (m, 3H), 4.91 (d, 1H, J=6.9 Hz), 4.70 (br. s, 3H), 3.89 (d, 1H, J=6.6 Hz), 3.57 (s, 3H), 2.75 (s, 3H), 2.44 (m, 4H), 1.98 (m, 1H), 1.84 (m, 2H), 1.75 (m, 1H), 1.27 (m, 1H). HRMS (ESI MS m/z) Calcd for C₂₇H₃₀ClN₆O₅ ⁺ (M+H)⁺ 553.1961, found 553.1970. Further elution with 20% methanol-ethyl acetate provided the title compound 7 (21%). ¹H NMR (CD₃OD): 7.96 (s, 1H), 7.31 (s, 1H), 7.15-7.22 (m, 3H), 4.97 (d, 1H, J=6.6 Hz), 4.75 (br. s., 3H), 3.90 (d, 1H, J=6.6 Hz), 2.76 (s, 3H), 2.41 (t, 2H, J=7.2 Hz), 2.29 (t, 2H, J=7.2 Hz), 1.96 (m, 1H), 1.83 (m, 3H), 1.74 (m, 1H), 1.26 (m, 1H). HRMS (ESI MS m/z) Calcd for C₂₆H₂₈ClN₆O₅ ⁺ (M+H)⁺ 539.1804, found 537.1673.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(1-ethynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (3). To a solution of compound 4 (10 mg) in THF (1 mL) was added 1M solution of tetrabutylammonium fluoride in THF (0.2 mL). The reaction mixture was stirred for 1 h, evaporated, and the residue was purified by flash chromatography (0% to 10% methanol-ethyl acetate) to afford the title compound 3. Yield 75%. ¹H NMR (CD₃OD) 8.1 (s, 1H), 7.41 (d, 1H, J=2.7 Hz), 6.89 (d, 1H, J=9.3 Hz), 6.78 (dd, 1H, J=2.7, 9.0 Hz), 5.06 (d, 1H, J=6.6 Hz), 4.83 (br. s., 2H), 3.99 (d, 1H, J=6.6 Hz), 2.87 (s, 3H), 2.06 (m, 1H), 1.83 (t, 1H, J=4.8 Hz), 1.38 (m, 1H). HRMS (ESI MS m/z) Calcd for C₂₂H₂₂ClN₆O₃ (M+H)+ 453.1437, found 453.1444.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-[5-(β-aminoethylaminocarbonyl)-1-pentynyl)]-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (8). To a solution of ester 6 (2.4 mg, 0.0045 mmol) in methanol (0.05 mL) was added ethylenediamine (1 mL). The reaction mixture was stirred at room temperature for 60 h, and was evaporated to dryness. The residue was purified by flash chromatography (30 to 70% MeOH-EtOAc) to afford the title amide 8 (2.0 mg, 0.0034 mmol, 76%). ¹H NMR: 7.98 (s, 1H), 7.31 (s, 1H), 7.16-7.22 (m, 3H), 4.92 (d, 1H, J=6.6 Hz), 4.69 (s, 1H), 4.74 (br. s, 2H, under HDO peak) 3.88 (d, 1H, J=6.6 Hz), 3.14 (m, 2H, J=6.3 Hz), 2.75 (s, 3H), 2.63 (t, 2H, J=6.3 Hz), 2.44 (m, 2H), 2.33 (t, 2H, J=7.5 Hz), 1.97 (m, 1H), 1.87 (m, 2H), 1.75 (t, 1H, J=4.8 Hz), 1.28 (m, 1H).

(1′S,2′R,3′S,4′S,5′S)-4′-6-[3-[5-(Methoxycarbonyl)-1-pentynyl]phenylmethylamino]-2-chloro-9-yl}-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (26) and (1′S,2′R,3′S,4′S,5′S)-4′-6-[3-[5-(hydroxycarbonyl)-1-pentynyl]phenylmethylamino]-2-chloro-9-yl}-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (9). To a solution of compound 25 (60 mg, 0.1 mmol), dichlorobis(triphenylphosphine)palladium(II) (14 mg, 0.02 mmol), and CuI (2 mg, 0.01 mmol) in DMF (0.1 mL) under nitrogen was added methyl co-hexynoate (63 mg, 0.5 mmol) and then triethylamine (202 mg, 1 mmol). The reaction was stirred at room temperature for 16 h, diluted with ethyl acetate, washed with water, dried, and evaporated. The residue was purified by flash chromatography (30% to 100% ethyl acetate-hexane) to afford corresponding 3-(5-methoxycarbonylpentyn-1-yl)phenylaminomethyl derivative. The product was dissolved in MeOH (6 mL), TFA (0.5 mL) and water (2 mL) were added, and the reaction mixture was stirred for 16 h at 70° C. The reaction mixture was evaporated, and the residue was purified by flash chromatography (0% to 10% methanol-ethyl acetate) to afford compounds title methyl ester 27 (28 mg, 0.051 mmol, 51%). ¹H NMR (CD₃OD) 8.04 (s, 1H), 7.39 (s, 1H), 7.24-7.32 (m, 3H), 5.06 (d, 1H, J=6.6 Hz), 4.80 (s, 1H), 4.72 (br. s, 2H), 3.99 (d, 1H, J=6.6 Hz), 3.64 (s, 3H), 2.85 (s, 3H), 2.48 (t, 2H, J=6.9 Hz), 2.45 (t, 2H, J=6.9 Hz), 2.04 (m, 1H), 2.01 (m, 2H), 1.80 (t, 1H, J=5.1 Hz), 1.36 (m, 1H). HRMS (ESI MS m/z) Calcd for C₂₇H₃₀ClN₆O₅ ⁺ (M+H)⁺ 553.1961, found 553.1981. Further elution with 20% MeOH-EtOAc provided the carboxylic acid 9 (12 mg, 0.028 mmol, 22%). ¹H NMR (DMSOd6) 8.89 (t, 1H, J=6.0 Hz), 8.10 (s, 1H), 7.57 (q, 1H, J=5.2, 4.8), 7.37 (s, 1H), 7.23-7.34 (m, 3H), 5.45 (br s, 1H), 4.94 (d, 1H, J=4.7 Hz), 4.84 (br s, 1H), 4.66 (s, 1H), 4.62 (d, 2H, J=4.8), 3.89 (d, 1H, J=5.1), 2.67 (d, 3H, J=3.9 Hz), 2.44 (t, 2H, J=6.9 Hz), 2.36 (t, 2H, J=8.1 Hz), 1.83 (m, 1H), 1.75 (m, 2H), 1.60 (t, 1H, J=5.2 Hz), 1.30 (m, 1H).

(1′S,1′R,3′S,4′S,5′S)-4′-6-[3-[5-(β-Aminoethylaminocarbonyl)-1-pentynyl]phenylmethylamino]-2-chloro-9-yl}-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (10). To a solution of ester 27 (60 mg, 0.11 mmol) in methanol (0.1 mL) was added ethylenediamine (2 mL). The reaction mixture was stirred at room temperature for 60 h, and was evaporated to dryness. The residue was purified by flash chromatography (30 to 70% MeOH-EtOAc) to afford the title amide 10 (57 mg, 0.98 mmol, 88%). ¹H NMR (CD₃OD) 8.14 (s, 1H), 7.51 (s, 1H), 7.15-7.31 (m, 3H), 5.17 (d, 1H, J=7.2 Hz), 4.91 (s, 1H), 4.83 (br. s, 2H) 4.10 (d, 1H, J=6.6 Hz), 3.35 (t, 3H, J=6.0 Hz), 2.96 (s, 3H), 2.82 (t, 2H, J=6.6 Hz), 2.56 (t, 2H, J=6.9 Hz), 2.49 (t, 2H, J=7.8 Hz), 2.16 (m, 1H), 2.01 (m, 2H), 1.91 (t, 1H, J=4.8 Hz), 1.47 (m, 1H). HRMS (ESI MS m/z) Calcd for C28H34ClN8O4+ (M+H)+ 581.2386, found 581.2392.

(1′S,2′R,3′S,4′S,5′S)-4′-6-[3-[5-(β-Acetylaminoethylaminocarbonyl)-1-pentynyl]phenylmethylamino]-2-chloro-9-yl}-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (11). To a solution of amine 10 (2 mg, 0.0034 mmol) in methanol (1 mL) was added acetic anhydride (10 mkL, 0.01 mmol). The reaction mixture was stirred for 16 h, evaporated, and the residue was evaporated with dioxane (3×1 mL) to afford compound 11 (2.2 mg, 0.0034 mL, quant. yield). ¹H NMR (CD₃OD) 7.93 (s, 1H), 7.15-7.22 (m, 4H), 4.97 (d, 1H, J=4.8 Hz), 4.70 (s, 1H), 4.62 (br. s, 2H) 3.90 (d, 1H, J=6.6 Hz), 3.16 (s, 4H), 2.76 (s, 3H), 2.36 (t, 2H, J=6.6 Hz), 2.26 (t, 2H, J=7.8 Hz), 1.95 (m, 1H), 1.82 (s, 3H), 1.77 (m, 2H), 1.72 (t, 1H, J=4.8 Hz), 1.28 (m, 1H). HRMS (ESI MS m/z) Calcd for C₃₀H₃₆ClN₈O₅ ⁺ (M+H)⁺ 623.2492 Found 623.2501.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(4-methoxycarbonyl-1-butynyl)-9-yl]-2′,3′-O-isopropylidenebicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (28) (FIG. 3). To a solution of compound 27 (52 mg, 0.087 mmol) in anhydrous DMF (1.5 mL), PdCl₂(PPh₃)₂ (12 mg, 0.017 mmol), CuI (2 mg, 0.010 mmol), methyl-co-pentynate (39 mg, 0.347 mmol) and then triethylamine (0.12 mL, 0.86 mmol) was added. The reaction mixture was stirred at room temperature for overnight. Solvent was evaporated under vacuum, and the residue was purified on flash silica gel column chromatography (CH₂Cl₂:MeOH=30:1) to give compound 28 (40 mg, 78%) as foamy syrup. ¹H NMR (CD₃OD, 300 MHz) δ 8.16 (s, 1H), 7.42-7.44 (m, 4H), 5.81 (d, J=6.7 Hz, 1H), 5.02 (s, 1H), 4.82 (m, 2H) 3.78 (s, 3H), 2.85 (s, 3H), 2.72-281 (m, 5H), 2.09-2.14 (m, 1H), 1.55 (s, 3H), 1.41 (t, J=5.1 Hz, 1H), 1.29 (s, 3H), 0.82-0.96 (m, 1H). HRMS calculated for C₂₉H₃₂ClN₆O₅ (M+H)⁺: 579.2105; found 579.2123.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(6-methoxycarbonyl-1-hexynyl)-9-yl]-2′,3′-O-isopropylidenebicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (30). Compound 30 (74%) was synthesized from 27 following the same procedure as for compound 28. ¹H NMR (CD₃OD, 300 MHz) δ 8.12 (s, 1H), 7.41-7.20 (m, 4H), 5.75 (d, J=6.9 Hz, 1H), 4.98 (s, 1H), 4.86 (m, 211), 3.66 (s, 3H), 2.84 (s, 3H), 2.38-2.55 (m, 4H), 2.06-2.15 (m, 1H), 1.64-1.91 (m, 4H), 1.53 (s, 3H), 1.38 (m, 1H), 1.24-1.32 (m, 4H), 0.84-0.97 (m, 1H). HRMS calculated for C₃₁H₃₆ClN₆O₅ (M+H)⁺: 607.2426; found 607.2436.

(1′S, 2′R, 3′S, 4′S, 5′S)-4′-[6-(3-Chlorobenzylamino)-2-(4-(β-aminoethylaminocarbonyl)-1-butynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (37). To a solution of compound 28 (20 mg. 0.034 mmol) in methanol (0.3 mL), ethylenediamine (1.5 mL) was added and stirred for overnight at room temperature. Solvent was evaporated and the residue was roughly purified on flash silica gel column chromatography. The aminated product was dissolved in methanol (1.5 mL) and 10% trifluoroacetic acid (1.5 mL) and heated at 70° C. for 15 h. Solvent was evaporated and the residue was purified on flash silica gel column chromatography (CH₂Cl₂:MeOH:NH₄OH=10:1:0.1) to give compound 37 (15 mg, 79%). ¹H NMR (CD₃OD, 300 MHz) δ 8.09 (s, 1H), 7.39 (s, 1H), 7.27-7.32 (m, 3H), 4.99 (d, J=6.6 Hz, 1H), 4.78-4.91 (m, 2H), 3.97 (d, J=6.6 Hz, 1H), 3.33-3.36 (m, 4H), 2.87 (s, 3H), 2.75-2.80 (m, 4H), 2.53 (t, 7.2 Hz, 2H), 2.59-3.41 (m, 1H), 1.88 (t, J=4.5 Hz, 1H), 1.34-1.43 (m, 1H). HRMS calculated for C₂₇H₃₁ClN₆O₂Na (M+Na)⁺: 589.2068; found 589.2054.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(6-(β-aminoethylaminocarbonyl)-1-hexynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (38). Compound 38 (82%) was synthesized from compound 30 following the same procedure as for compound 37. NMR (CD₃OD, 300 MHz) δ 8.06 (s, 1H), 7.40 (s, 1H), 7.28-7.31 (m, 3H), 5.01 (d, J=6.7 Hz, 1H), 4.84 (m, 2H), 3.98 (d, J=6.7 Hz, 1H), 3.24 (t, J=6.3 Hz, 2H), 2.85 (s, 3H), 2.72 (t, J=6.3 Hz, 2H), 2.48 (t, J=6.2 Hz, 2H), 2.27 (t, J=7.5 Hz, 2H), 2.23 (m, 1H), 1.74-1.88 (m, 3H), 1.60-1.73 (m, 2H), 1.32-1.42 (m, 1H), 0.81-0.98 (m, 1H). HRMS calculated for C₂₉H₃₆ClN₈O₄ (M+H)⁺: 595.2527; found 595.2548.

(1′S, 2′R, 3′S, 4′S, 5′S)-4′[6-(3-Chlorobenzylamino)-2-4-(β-aminopropylaminocarbonyl)-1-butynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (39). Compound 39 (78%) was synthesized from compound 28 following the same procedure as for compound 37. ¹H NMR (CD₃OD, 300 MHz) δ 8.09 (s, 1H), 7.39 (s, 1H), 7.25-7.32 (m, 3H), 5.03 (d. J=6.6 Hz, 1H), 4.81-4.86 (m, 2H), 4.99 (d. J=6.6 Hz, 1H), 3.35-3.37 (m, 2H), 2.87 (s, 3H), 2.67-2.82 (m, 4H), 2.52 (t, J=6.9 Hz, 2H), 2.06-2.10 (m, 1H), 1.85 (t, J=3.6 Hz, 1H), 1.62-1.71 (m, 2H), 1.36-1.40 (m, 1H), 0.78-0.92 (m, 1H). HRMS calculated for C₂₈H₃₄ClN₈O₄ (M+H)⁺: 581.2392; found 581.2376.

(1′S, 2′R, 3′S, 4′S, 5′S)-4′-[6-(3-Chlorobenzylamino)-2-(4-(β-aminobutylaminocarbonyl)-1-butynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (40). Compound 40 (74%) was synthesized from compound 28 following the same procedure as for compound 37. ¹H NMR (CD₃OD, 300 MHz) δ 8.09 (s, 1H), 7.40 (s, 1H), 7.28-7.32 (m, 3H), 5.04 (d, J=5.9 Hz, 1H), 4.82-4.86 (m, 2H), 3.99 (d, J=6.0 Hz, 1H), 3.34-3.38 (m, 2H), 2.87 (s, 3H), 2.69-2.82 (m, 4H), 248-2.54 (m, 2H), 2.06-2.10 (m, 1H), 1.86 (t, J=5.1 Hz, 1H), 1.52-1.56 (m, 4H), 1.36-1.41 (m, 1H), 0.76-0.97 (m, 1H). HRMS calculated for C₂₉H₃₆ClN₈O₄ (M+H)⁺: 595.2548; found 595.2533.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(4-(β-aminoethyl-N-aminoethylaminocarbonyl)-1-butanyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (41). Compound 41 (69%) was synthesized from compound 28 following the same procedure as for compound 37. ¹H NMR (CD₃OD, 300 MHz) δ 8.10 (s, 1H), 7.40 (s, 1H), 7.25-7.33 (m, 3H), 5.05 (d, J=5.4 Hz, 1H), 4.78-4.86 (m, 2H), 4.01 (d, J=6.3 Hz, 1H), 3.33-3.36 (m, 4H), 2.87 (s, 3H), 2.73-2.86 (m, 6H), 2.58 (t, J=6.9 Hz, 2H), 2.06-2.10 (m, 1H), 1.86 (t, J=5.1 Hz, 1H), 1.36-1.41 (m, 1H), 0.88-0.94 (m, 1H). HRMS calculated for C₂₉H₃₇ClN₉O₄ (M+H)⁺: 610.2657; found 610.2676.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(4-methoxycarbonyl)-1-butynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (35). A solution of compound 28 (67 mg, 0.115 mmol) in methanol (3 mL) and 10% trifluoromethanesulfonic acid (2 mL) was heated at 70° C. for overnight. Solvent was evaporated and the residue was purified on flash silica gel column chromatography (CH₂Cl₂:MeOH=20:1) to give compound 35 (46 mg, 75%). ¹H NMR (CD₃OD, 300 MHz) δ 8.13 (s, 1H), 7.40 (s, 1H), 7.22-7.45 (m, 3H), 5.10 (d, J=6.3 Hz, 1H), 4.80-4.86 (m, 2H), 4.03 (d, J=6.6 Hz, 1H), 3.63 (s, 3H), 2.86 (s, 3H), 2.76-2.85 (m, 2H), 2.46-2.58 (m, 2H), 2.05-2.10 (m, 1H), 1.77-1.83 (m, 1H), 1.35-1.40 (m, 1H), 0.82-0.96 (m, 1H). HRMS calculated for C₂₆H₂₈ClN₆O₅ (M+H)⁺: 539.1731; found 539.1743.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(6-methoxycarbonyl)-1-hexynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (36). Compound 36 (71%) was synthesized from compound 30 following the same procedure as for compound 35. ¹H NMR (CD₃OD, 300 MHz) δ 8.11 (s, 1H), 7.43 (s, 1H), 7.24-7.45 (m, 3H), 5.02 (d, J=6.3 Hz, 1H), 4.80-4.86 (m, 2H), 3.99 (d, J=6.6 Hz, 1H), 3.67 (s, 3H), 2.87 (s, 3H), 2.51 (t, J=6.9 Hz, 2H), 2.42 (t, J=7.5 Hz, 2H), 2.07-2.1 (m, 1H), 1.66-1.88 (m, 4H), 1.35-1.40 (m, 2H), 0.98-1.21 (m, 1H). HRMS calculated for C₂₈H₃₂ClN₆O₅ (M+H)⁺: 567.2123; found 567.2114.

(1′S,2′R,3′S,4′S,5S)-4′-[6-(3-Chlorobenzylamino)-2-(4-hydroxycarbonyl)-1-butynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (33). To a solution of ester 35 (30 mg, 0.055 mmol) in methanol (1.5 mL), 1M solution of potassium hydroxide (1 mL) was added and stirred at room temperature for overnight. The reaction mixture was neutralized with acetic acid and solvent was evaporated and the residue was purified on flash silica gel column chromatography (CH₂Cl₂:MeOH=10:1) to give compound 33 (23 mg, 80%). ¹H NMR (CD₃OD, 300 MHz) δ 8.06 (s, 1H), 7.38 (s, 1H), 7.24-7.35 (m, 3H), 5.14 (d, J=5.8 Hz, 1H), 4.79-4.86 (m, 2H), 4.03 (d, J=6.3 Hz, 1H), 2.87 (s, 3H), 2.42-2.80 (m, 4H), 2.04-2.32 (m, 1H), 1.82 (t, J=4.8 Hz, 1H), 1.36-1.40 (m, 1H), 0.84-0.97 (m, 1H). HRMS calculated for C₂₅H₂₆ClN₆O₅ (M+H)⁺: 525.9562; found 525.9583.

(1′S,2′R,3′S,4′S,5S)-4′-[6-(3-Chlorobenzylamino)-2-(4-hydroxycarbonyl)-1-hexynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (34). Compound 34 (77%) was prepared from compound 35 following the same method as for compound 33. ¹H NMR (CD₃OD, 300 MHz) δ 8.08 (s, 1H), 7.43 (s, 1H), 7.24-7.42 (m, 3H), 5.06 (d, J=6.6 Hz, 1H), 4.81-4.85 (m, 2H), 4.02 (d, J=6.0 Hz, 1H), 2.87 (s, 3H), 2.50 (t, J=6.9 Hz, 2H), 2.35 (t, J=7.5 Hz, 2H), 2.12-2.04 (m, 1H), 1.70-1.87 (m, 4H), 1.35-1.40 (m, 2H), 0.84-0.96 (m, 1H). HRMS calculated for C₂₇H₃₀ClN₆O₅ (M+H)⁺: 553.1966; found 553.1976.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(N-biotinyl(β-aminoethylaminocarbonyl)-1-butynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (42). To a solution of compound 37 (4 mg, 0.007 mmol) in dry DMF (0.5 mL), biotin (1.89 mg, 0.0077 mmol), HATU (3.2 mg, 0.0084 mmol) and DIEA (1.6 μL, 0.009 mmol) was added and stirred at room temperature for overnight. Solvent was evaporated and the residue was purified on flash silica gel column chromatography (CH₂Cl₂:MeOH:NH₄OH=5:1:0.1) to give compound 42 (3.5 mg, 62%). ¹H NMR (CD₃OD, 300 MHz) δ 8.14 (s, 1H), 7.43 (s, 1H), 7.29-7.39 (m, 3H), 5.07 (d, J=6.9 Hz, 1H), 4.78-4.86 (m, 2H), 4.48-4.52 (m, 1H), 4.28-4.32 (m, 1H), 4.04 (d, J=6.3 Hz, 1H), 3.70-3.82 (m, 2H), 3.24-3.31 (m, 1H), 3.08-3.23 (m, 1H), 2.91 (s, 3H), 2.70-2.83 (m, 4H), 2.56 (t, J=7.5 Hz, 2H), 2.04-2.15 (m, 2H), 1.89 (t, J=5.1 Hz, 111), 1.33-1.70 (m, 10H), 0.84-1.02 (m, 1H). HRMS calculated for C₃₇H₄₆ClN₁₀O₆S (M+H)⁺: 793.3011; found 793.3030.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(N-biotinyl{5-aminopentanyl}(β-aminoethylaminocarbonyl)-1-butynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (43). To a solution of compound 37 (3.4 mg, 0.0059 mmol) in DMF (0.5 mL), sulfo-NHS-LC-Biotin (10 mg, 0.017 mmol) and a drop of triethyl amine was added and stirred for overnight at room temperature. Solvent was evaporated and the residue was purified on flash silica gel column chromatography (CH₂Cl₂:MeOH:NH₄OH=7:1:0.1) to give compound 43 (2.9 mg, 55%). %). ¹H NMR (CD₃OD, 300 MHz) δ 7.99 (s, 1H), 7.29 (s, 1H), 7.19-7.32 (m, 3H), 4.93 (d, J=5.4 Hz, 1H), 4.70-4.80 (n, 2H), 4.36-4.42 (m, 1H), 4.16-4.22 (m, 1H), 3.88 (d, J=6.9 Hz, 1H), 3.42-3.62 (m, 2H), 3.03-3.15 (m, 4H), 2.89 (s, 3H), 2.56-2.86 (m, 6H), 2.41 (t, J=6.6 Hz, 1H), 1.96-2.13 (m, 5H), 1.15-1.16 (m, 14H), 0.74-0.88 (m, 1H). C₄₃H₅₇ClN₁₁O₇S (M+H)⁺: 906.3852; found 906.3878.

(1′S,2′R,3′S,4′S,5′S)-4′-[6-(3-Chlorobenzylamino)-2-(N-Cyanine(β-aminoethylaminocarbonyl)-1-butynyl)-9-yl]-2′,3′-dihydroxybicyclo[3.1.0]hexane-1′-carboxylic acid N-methylamide (44). To a solution of compound 37 (1.69 mg, 0.0029 mmol) in DMF (0.3 mL), Cy5 fluoroscent dye (2.36 mg, 0.0029 mmol) and bicarbonate buffer (60 μL) was added and stirred at room temperature for overnight. The reaction mixture was covered with aluminum foil in order to protect from light. Solvent was evaporated and the residue was purified on flash silica gel column chromatography (CH₂Cl₂:MeOH:NH₄OH=3:1:0.1) to give compound 44 (3.2 mg, 89%) as a dark blue syrup. ¹H NMR (CD₃OD, 300 MHz) δ 8.21-8.42 (m, 1H), 8.08 (s, 1H), 7.85-7.93 (m, 2H), 7.29-7.46 (m, 6H), 6.28-6.45 (m, 1H), 5.07 (d, J=6.9 Hz, 1H), 4.84-4.86 (m, 2H), 3.97-4.20 (m, 3H), 3.53 (t, J=6.0 Hz, 2H), 3.12 (t, J=6.0 Hz, 2H), 2.89 (s, 3H), 2.49 (t, J=7.5 Hz, 2H), 2.52-2.64 (m, 2H), 2.01-2.17 (m, 2H), 1.56-1.89 (m, 9H), 1.22-1.49 (m, 10H), 0.86-0.96 (m, 1H).

HRMS calculated for C₆₀H₆₈ClIN₁₀O₁₁S₂ (M⁺): 1203.4199; found 1203.4175.

Example 2

This example illustrates some of the biological properties of compounds in accordance with an embodiment of the invention.

[¹²⁵I]N⁶-(4-amino-3-iodo-benzyl)adenosine-5′-N-methyluronamide ([¹²⁵I]I-AB-MECA; 2000 Ci/mmol), [³H]R-PIA (R—N⁶-[phenylisopropyl]adenosine, 34 Ci/mmol), [³H]CGS21680 (2-[p-(2-carboxyethyl)phenylethylamino]-5′-N-ethylcarboxamido-adenosine, 47 Ci/mmol) and [³H]cAMP (40 Ci/mmol) were from Amersham Pharmacia Biotech (Buckinghamshire, UK). NECA, CGS21680, CPA, and R-PIA were purchased from Sigma-RBI (St. Louis, Mo.). Other chemicals were from standard commercial sources and of analytical grade.

CHO cells stably expressing human recombinant ARs were cultured in DMEM and F12 (1:1) supplemented with 10% fetal bovine serum, 100 units/ml penicillin, 100 μg/mL streptomycin, 2 μmol/ml glutamine and 800 μg/ml geneticin. After harvest and homogenization, cells were centrifuged at 500 g for 10 min, and the pellet was re-suspended in 50 mM Tris.HCl buffer (pH 7.4) containing 10 mM MgCl₂, 1 mM EDTA. The suspension was homogenized with an electric homogenizer for 10 sec, and was then re-centrifuged at 20,000 g for 20 min at 4° C. The resultant pellets were resuspended in buffer in the presence of 3 Units/ml adenosine deaminase, and the suspension was stored at −80° C. until the binding experiments. The protein concentration was measured as described in Bradford, M. M. et al., Anal. Biochem, 1976, 72, 248. For A₃AR binding assays, each tube contained 100 μl of membrane suspension, 50 μl of [¹²⁵I]I-AB-MECA (final concentration 0.5 nM), and 50 μl of increasing concentrations of compounds in Tris.HCl buffer (50 mM, pH 7.4) containing 10 mM MgCl₂. Nonspecific binding was determined using 10 μM NECA. The mixtures were incubated at 25° C. for 60 min. Binding reactions were terminated by filtration through WHATMAN™ GF/B filters under reduced pressure using a MT-24 cell harvester (Brandell, Gaithersburg, Md.). Filters were washed three times with ice-cold buffer. Radioactivity was determined in a Beckman 5500γ-counter. The binding of [³H]R-PIA to A₁ARs and the binding of [³H]CGS21680 to A_(2A)ARs were as previously described.¹⁰ Similar competition binding assays were conducted using HEK 293 cell membranes expressing mouse ARs using [¹²⁵I]I-AB-MECA to label A₁ or A₃ARs and [³H]CGS 21680 to label A_(2A)ARs as described in Kreckler L M et al., J Pharmacol, Exp. Ther. 2006, 317, 172. IC₅₀ values were converted to K_(i) values as described in Cheng Y-C and Prusoff W H., Biochem. Pharmacol. 1973, 22, 3099. Data were expressed as mean±standard error and set forth in Table 1.

TABLE 1 Affinity of a series of (N)-methanocarba adenosine derivatives at three subtypes of ARs in various species.

Affinity A₂A^(a) A₁ ^(a) K_(i), nM A3^(a) Selectivity Cmpd. R¹ R² Species K_(i), nM (or % inhib.) K_(i), nM A₁/A₃ 1 3-chlorobenzyl I M  210 ± 34.4 (40%)^(i) 1.18 ± 0.11 178 H^(c) 2200 >10000 3.6 610 R^(c) ND ND 3.9 — 2 2,5-dimethoxybenzyl I M 293 ± 29 (14%)^(i) 1.51 ± 0.36 194 H 3070 ± 820 (35%)^(f) 1.30 ± 0.27 2360 3 3-chlorobenzyl ethynyl M 45.6 ± 7.9 (41%)^(i) 0.85 ± 0.08 53.6 H 174 ± 23 (48%)^(f) 1.30 ± 0.38 134 4 3-chlorobenzyl 2-trimethylsilyl-ethynyl M 159 ± 22 (20%)^(i) 4.46 ± 0.57 35.6 H 160 ± 40 (52%)^(f) 0.98 ± 0.14 160 5 3-chlorobenzyl 1-pentynyl M 1390 ± 430 (42%)^(i) 6.06 ± 1.21 229 H 1040 ± 83  (80%)^(f) 0.82 ± 0.20 1300 6 3-chlorobenzyl 5-carbomethoxy-1-pentynyl M 1340 ± 330 (50%)^(i) 4.65 ± 0.53 288 H 482 ± 23 (49%)^(f) 1.17 ± 0.27 412 7 3-chlorobenzyl 5-carboxy-1-pentynyl M 10500 ± 1900 (8%)^(i) 24.4 ± 3.1  431 H 14900 ± 3500 (43%)^(f) 2.38 ± 0.56 6260 8 3-chlorobenzyl 5-(2-aminoethyl)aminocarbonyl- M 546 ± 62 (31%)^(i) 8.60 ± 1.02 64 1-pentynyl H 454 ± 44 (81%)^(f) 2.17 ± 0.51 209 9 3-(5-carboxy-1- Cl M 703 ± 71 (5%)^(i) 14.4 ± 2.5  49 pentynyl)benzyl H 320 ± 31 (14%)^(f) 17.1 ± 1.2  19 10 3-(5-(2-aminoethyl) Cl M 151 ± 18 (39%)^(i) 11.9 ± 2.4  13 aminocarbonyl- 1-pentynyl)benzyl H 271 ± 23 (58%)^(f) 5.21 ± 0.91 52 11 3-(5-(2-acetamido- Cl M 45.4 ± 3.4 (68%)^(i) 4.65 ± 0.22 9.8 ethypaminocarbonyl- 1-pentynyl)benzyl H 181 ± 22 (80%)f 2.88 ± 0.54 63 12 Methyl Cl M 55.3 ± 6.0 20400 ± 3200 49.0 ± 3.9  1.1 H  2011 ± 1700 (6%)^(d,f) 2.2 ± 0.6 950 R^(d,g) 805^(g) >10,000^(g) 160 ± 30  5.0 13 3-Chlorobenzyl Cl M 15.3 ± 5.8 10400 ± 1700 1.49 ± 0.46 10.3 H^(c,d) 260 ± 60 2300 ± 100 0.29 ± 0.04 900 R^(d) ND ND 1.0 14 3-Bromobenzyl Cl M  8.79 ± 0.12 6390 ± 870 0.90 ± 0.22 9.8 H^(c,d) 270 1300 0.38 710 R^(c) ND ND 0.76 — 15 3-Iodobenzyl Cl M 7.32 ± 1.5 5350 ± 860 0.80 ± 0.14 9.2 H^(c) 136 ± 22 784 ± 97 1.5 ± 0.2 100 R 83.9^(g) 1660^(g) 1.1 76 16 3-(3-Hydroxy-1-propynyl)benzyl Cl M 111 ± 22 (11%)^(i) 1.94 ± 1.1  57.2 H^(d) 2600 ± 300 (56%)^(f) 2.9 ± 0.7 900 R^(d) ND ND 1.6 ± 0.6 17 2,5-Dimethoxybenzyl Cl M 29.0 ± 3.3 44700 ± 5700 1.72 ± 0.04 17 H^(c,d) 1600 10000 1.4 1100 R^(d) ND ND 0.87 18 2,2-Diphenylethyl Cl M 6.83 ± 1.5 1810 ± 581 1.67 ± 0.09 4.1 H^(c,e) 1300 ± 100 1600 ± 100 0.69 ± 0.02 1900 R^(c) ND ND 10 ± 4  19 Cyclopropylphenyl Cl M 6.60 ± 1.3 38200 ± 5300 2.79 ± .089 2.4 H^(c,d) 770 ± 50 4800 ± 200 0.78 ± 0.06 990 20 3-Chlorobenzyl SMe M  98.9 ± 18.8 (32%)^(i) 1.19 ± 0.09 83 H^(c) 610 10000 1.5 410 21 Methoxy Cl M 1160 ± 130 (2%)^(i) 877 ± 149 1.3 H 265 ± 45 (2%)^(f) 149 ± 15  1.8 31 3-Iodobenzyl H H  700 ± 270 6200 ± 100 2.4 ± 0.5 100^(j) 32 cyclopentyl Cl H 18.3 ± 6.3 3250 ± 300 3.7 ± 0.9 101^(j) 33 3-Chlorobenzyl C≡C(CH₂)₂COOH H  (17 ± 3%)  (24 ± 12%) 61.1 ± 35.8 106.2 ± 17.7^(j) 34 3-Chlorobenzyl C≡C(CH₂)₄COOH H  (5 ± 3%)  (38 ± 2%) 12.4 ± 1.8  ND 35 3-Chlorobenzyl C≡C(CH₂)₂COOCH₃ H  (19 ± 3%)  (43 ± 5%) 5.5 ± 0.3 74.4 ± 5.1^(j) 36 3-Chlorobenzyl C≡C(CH₂)₄COOCH₃ H  (21 ± 8%)  3540 ± 1370 11.1 ± 2.3  90.0 ± 6.2^(j) 37 3-Chlorobenzyl C≡C(CH₂)₂CONH(CH₂)₂NH₂ H  (25 ± 12%) 550 ± 83 2.5 ± 0.5 ND 38 3-Chlorobenzyl C≡C(CH₂)₄CONH(CH₂)₂NH₂ H  (21 ± 6%) 277 ± 33 3.4 ± 0.7 100.0 ± 2.4^(j) 39 3-Chlorobenzyl C≡C(CH₂)₂CONH(CH₂)₃NH₂ H  (16 ± 4%)  979 ± 181 3.1 ± 0.4  97.9 ± 18.4^(j) 40 3-Chlorobenzyl C≡C(CH₂)₂CONH(CH₂)₄NH₂ H  (30 ± 7%)  766 ± 109 2.1 ± 0.4 102.1 ± 13.0^(j) 41 3-Chlorobenzyl C≡C(CH₂)₂CO[NH(CH₂)₂]₂NH₂ H  (14 ± 8%)  890 ± 110 15.4 ± 4.4   87.6 ± 21.2^(j) 42 3-Chlorobenzyl C≡C(CH₂)₂CONH(CH₂)₂NH-biotin H  (13 ± 6%)  (51 ± 2%) 36.4 ± 5.6   84.5 ± 12.0^(j) 43 3 -Chlorobenzyl C≡C(CH₂)₂CONH(CH₂)₂NH- H  (8 ± 4%)  (47 ± 11%) 57.7 ± 16.2 106.5 ± 17.7^(j) CO(CH₂)₅NH-biotin 44 3-Chlorobenzyl C≡C(CH₂)₂CONH(CH₂)₂NH- H  (10 ± 4%)  4730 ± 1020 17.2 ± 3.1  94.4 ± 9.6^(i) CO—(CH₂)₅Cy5 a) Competition radioligand binding assays using [¹²⁵I]N⁶-(4-amino-3-iodobenzyl)adenosine-5′-N-methyl-uronamide (A₁ and A₃ARs) and [³H]2-[p- (2-carboxyethyl)phenyl-ethylamino]-5′-N-ethylcarboxamidoadenosine (A_(2A)AR) were conducted with membranes prepared from HEK293 cells expressing recombinant mouse A₁, A_(2A), or A₃ARs. At rat and human ARs, the A₁ radioligand was either [³H]R-phenylisopropyladenosine or [³H]2-chloro-N⁶-cyclopentyladenosine. Values are expressed as the mean ± SEM. ND, not determined. b) Data from Ge et al. (J. Pharmacal. Exp. Ther., 2006, 319, 1200). c) EC₅₀ value in activation of the A_(2B)AR is ≧ 10 μM. d) Data from Tchilibon et al. (J. Med. Chem., 2005, 48, 1745). e) Data from Kim et al. (J. Med. Chem., 1994, 37, 3614). f) Percent Inhibition at 10 μM. g) Data from Lee et al. (Bioorg. Med. Chem. Lett., 2001, 11, 1333). i) Percent Inhibition at 100 μM. j) %Efficacy at the human A₃ AR was determined by inhibition of forskolin-stimulated cyclic AMP production in AR transfected CHO cells. Data are at 10 μM in comparison to the maximal effect of a full agonist (5′-N-ethylcarboxamidoadenosine) at 100%.

All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

The use of the terms “a” and “an” and “the” and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms (i.e., meaning “including, but not limited to,”) unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context. 

The invention claimed is:
 1. A compound of Formula I:

wherein: R¹ is selected from the group consisting of C₁-C₆ alkyl, C₁-C₆ alkoxy, hydroxyl, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkyl C₁-C₆ alkyl, C₃-C₈ dicycloalkyl C₁-C₆ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₆ alkyl, C₇-C₁₄ tricycloalkyl C₁-C₆ alkyl, C₆-C₁₄ aryl, C₆-C₁₄ aryl C₁-C₆ alkyl, C₆-C₁₄ diaryl C₁-C₆ alkyl, C₆-C₁₄ aryl C₁-C₆ alkoxy, heterocyclyl C₁-C₆ alkyl, heterocyclyl, 4-[[[4-[[[(2-amino C₁-C₆ alkyl)amino]-carbonyl]-C₁-C₆ alkyl]anilino]carbonyl]C₁-C₆ alkyl]C₆-C₁₄ aryl, and C₆-C₁₄ aryl C₃-C₈ cycloalkyl, wherein the aryl or heterocyclyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, hydroxyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₁-C₆ alkoxy, C₆-C₁₄ aryloxy, hydroxy C₁-C₆ alkyl, hydroxy C₂-C₆ alkenyl, hydroxy C₂-C₆ alkynyl, carboxy C₁-C₆ alkyl, carboxy C₂-C₆ alkenyl, carboxy C₂-C₆ alkynyl, aminocarbonyl C₁-C₆ alkyl, aminocarbonyl C₂-C₆ alkenyl, aminocarbonyl C₂-C₆ alkynyl, and any combination thereof; and the alkyl or cycloalkyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, alkyl, alkoxy, aryloxy, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, aminocarbonylalkoxy, and arylalkoxy, and any combination thereof; or R¹ is 7-norbornyl; R² is selected from the group consisting of C₇-C₁₂ cycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkenyl C₁-C₂₀ alkyl, C₆-C₁₄ aryl C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkenyl, C₆-C₁₄ aryl C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₁-C₂₀ alkyl C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, and C₆-C₁₄ aryl C₂-C₂₀ alkynyl, and the alkyl, cycloalkyl, or aryl portion of R² is optionally substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, mercapto, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof; or R² is selected from the group consisting of amino (alkylene-NH—)_(n) alkylaminocarbonyl wherein n is 1 to 6, aminoalkylcarbonylaminoalkylaminocarbonyl, aminoalkylaminocarbonyl whose amino end is linked to a label, dye, or reporter group, amino (alkylene-NH—)_(n) alkylaminocarbonyl wherein n is 1 to 6 whose amino end is linked to a label, dye, or reporter group, and aminoalkylcarbonylaminoalkylaminocarbonyl whose amino end is linked to a label, dye, or reporter group; R³ and R⁴ are independently selected from the group consisting of hydroxyl, amino, mercapto, ureido, C₁-C₆ alkyl carbonylamino, hydroxy C₁-C₆ alkyl, and hydrazinyl; and R⁵ is selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl)aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, hydrazinyl, amino C₁-C₃ alkyl, C₃-C₆ cycloalkylamino, hydroxylamino, and C₂-C₃ alkenyl; or a pharmaceutically acceptable salt thereof.
 2. The compound of claim 1, wherein: R¹ is selected from the group consisting of C₁-C₆ alkyl, C₁-C₆ alkoxy, hydroxyl, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkyl C₁-C₆ alkyl, C₃-C₈ dicycloalkyl C₁-C₆ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₆ alkyl, C₇-C₁₄ tricycloalkyl C₁-C₆ alkyl, C₆-C₁₄ aryl, C₆-C₁₄ aryl C₁-C₆ alkyl, C₆-C₁₄ diaryl C₁-C₆ alkyl, C₆-C₁₄ aryl C₁-C₆ alkoxy, heterocyclyl C₁-C₆ alkyl, heterocyclyl, 4-[[[4-[[[(2-amino C₁-C₆ alkyl)amino]-carbonyl]-C₁-C₆ alkyl]anilino]carbonyl]C₁-C₆ alkyl]C₆-C₁₄ aryl, and C₆-C₁₄ aryl C₃-C₈ cycloalkyl, wherein the aryl or heterocyclyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, hydroxyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, C₁-C₆ alkyl, C₂-C₆ alkenyl, C₂-C₆ alkynyl, C₁-C₆ alkoxy, C₆-C₁₄ aryloxy, hydroxy C₁-C₆ alkyl, hydroxy C₂-C₆ alkenyl, hydroxy C₂-C₆ alkynyl, carboxy C₁-C₆ alkyl, carboxy C₂-C₆ alkenyl, carboxy C₂-C₆ alkynyl, aminocarbonyl C₁-C₆ alkyl, aminocarbonyl C₂-C₆ alkenyl, aminocarbonyl C₂-C₆ alkynyl, and any combination thereof; and the alkyl or cycloalkyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, alkyl, alkoxy, aryloxy, hydroxyalkyl, hydroxyalkenyl, hydroxyalkynyl, aminocarbonylalkoxy, and arylalkoxy, and any combination thereof; or R¹ is 7-norbornyl; R² is selected from the group consisting of C₇-C₁₂ cycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkenyl C₁-C₂₀ alkyl, C₆-C₁₄ aryl C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkenyl, C₆-C₁₄ aryl C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, and C₆-C₁₄ aryl C₂-C₂₀ alkynyl, and the alkyl, cycloalkyl, or aryl portion of R² is optionally substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, mercapto, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof; R³ and R⁴ are independently selected from the group consisting of hydroxyl, amino, mercapto, ureido, C₁-C₆ alkyl carbonylamino, hydroxy C₁-C₆ alkyl, and hydrazinyl; and R⁵ is selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl)aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, hydrazinyl, amino C₁-C₃ alkyl, C₃-C₆ cycloalkylamino, hydroxylamino, and C₂-C₃ alkenyl; or a pharmaceutically acceptable salt thereof.
 3. A compound of Formula I:

wherein R¹ is selected from the group consisting of C₁-C₆ alkyl, C₃-C₈ cycloalkyl, C₆-C₁₄ aryl C₁-C₆ alkyl, C₆-C₁₄ diaryl C₁-C₆ alkyl, C₆-C₁₄ aryl C₃-C₈ cycloalkyl, and heterocyclyl C₁-C₆ alkyl, wherein the aryl or heterocyclyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, C₁-C₆ alkyl, alkoxy, C₆-C₁₄ aryloxy, hydroxy C₁-C₆ alkyl, hydroxy C₂-C₆ alkenyl, hydroxy C₂-C₆ alkynyl, aminocarbonyl C₁-C₆ alkoxy, and C₆-C₁₄ aryl C₁-C₆ alkoxy, and any combination thereof; R² is selected from the group consisting of C₇-C₁₂, cycloalkyl C₁-C₂₀ alkyl, C₂-C₁₂ bicycloalkyl C₁-C₂₀ alkyl, C₂-C₁₂ bicycloalkenyl C₁-C₂₀ alkyl, C₆-C₁₂ aryl C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkenyl, C₆-C₁₄ aryl C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₁-C₂₀ alkyl C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, and C₆-C₁₄ aryl C₂-C₂₀ alkynyl, and the alkyl, cycloalkyl, or aryl portion of R² is optionally substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, mercapto, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof; or R² is selected from the group consisting of amino (alkylene-NH—)_(B) alkylaminocarbonyl wherein n is 1 to 6, aminoalkylcarbonylaminoalkylaminocarbonyl, aminoalkylaminocarbonyl whose amino end linked to a label, dye, or reporter group, amino (alkylene-NH—)_(n) alkylaminocarbonyl wherein n is 1 to 6 whose amino end is linked to a label, dye, or reporter group, and aminoalkylcarbonylaminoalkylaminocarbonyl whose amino end is linked to a label, dye, or reporter group; R³ and R⁴ are independently selected from the group consisting of hydroxyl, amino mercapto, ureido, C₁-C₆ alkyl carbonylamino, hydroxy C₁-C₆ alkyl, and hydrazinyl; and R⁵ is selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl)aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, hydrazinyl, amino C₁-C₃ alkyl, C₃-C₁₂ cycloalkylamino, hydroxylamino, and C₂-C₁₂ alkenyl; or a pharmaceutically acceptable salt thereof.
 4. The compound of claim 1, wherein R¹ is selected from the group consisting of methyl, cyclopentyl, benzyl, diphenyl ethyl, phenyl cyclopropyl, diphenyl cyclopropyl, and 2,2,-diphenylethyl, wherein the phenyl portion of R¹ is optionally substituted with one or more substituents selected from the group consisting of halo, amino, hydroxyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, C₁-C₆ alkyl, C₁-C₆ alkoxy, phenoxy, hydroxy C₁-C₆ alkyl, hydroxy C₂-C₆ alkenyl, hydroxy C₂-C₆ alkynyl, and any combination thereof, or a pharmaceutically acceptable salt thereof.
 5. The compound of claim 1, wherein R¹ is benzyl which is optionally substituted with one or more substituents selected from the group consisting of halo, amino, hydroxyl, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, C₁-C₆ alkyl, C₁-C₆ alkoxy, phenoxy, hydroxy C₁-C₆ alkyl, hydroxy C₂-C₆ alkenyl, hydroxy C₂-C₆ alkynyl, and any combination thereof, or a pharmaceutically acceptable salt thereof.
 6. The compound of claim 1, wherein R¹ is benzyl or benzyl substituted with one or more substituents selected from the group consisting of halo, amino, methyl, methoxy, phenoxy, hydroxymethyl, hydroxypropynyl, carboxypropynyl, alkoxycarbonylpropynyl, aminocarbonyl methoxy, and benzyloxy, and any combination thereof, or a pharmaceutically acceptable salt thereof.
 7. The compound of claim 1, wherein R¹ is methyl, cyclopentyl, or 7-norbornyl, or a pharmaceutically acceptable salt thereof.
 8. The compound of claim 1, wherein R¹ is selected from the group consisting of 3-chlorobenzyl, 3-bromobenzyl, 3-iodobenzyl, 3-(3-hydroxypropynyl)benzyl, and 2,5-dimethoxybenzyl, or a pharmaceutically acceptable salt thereof.
 9. The compound of claim 4, wherein R¹ is trans-2-phenyl-1-cyclopropyl or 2,2-diphenylethyl, or a pharmaceutically acceptable salt thereof.
 10. The compound of claim 1, wherein R² is selected from the group consisting of C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, and C₆-C₁₄ aryl C₂-C₂₀ alkynyl, or a pharmaceutically acceptable salt thereof.
 11. The compound of claim 1, wherein R² is C₂-C₂₀ alkynyl, or a pharmaceutically acceptable salt thereof.
 12. The compound of claim 1, wherein the alkyl, cycloalkyl, or aryl portion of R² is substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, mercapto, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof, or a pharmaceutically acceptable salt thereof.
 13. The compound of claim 1, wherein R³ and R⁴ are independently selected from the group consisting of hydroxyl, amino, mercapto, and ureido, or a pharmaceutically acceptable salt thereof.
 14. The compound of claim 1, wherein R⁵ is selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl)aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, amino C₁-C₃ alkyl, and C₃-C₆ cycloalkylamino, or a pharmaceutically acceptable salt thereof.
 15. The compound of claim 1, wherein R¹ is 3-chlorobenzyl, 3-iodobenzyl, or cyclopentyl, R² is ethynyl, R³ and R⁴ are hydroxyl, and R⁵ is methylamino carbonyl, or a pharmaceutically acceptable salt thereof.
 16. The compound of claim 1, wherein R¹ is 3-chlorobenzyl, R² is 2-(trimethylsilyl)ethynyl, 1-pentynyl, 5-methoxycarbonyl-1-pentynyl, 5-carboxy-1-pentynyl, or 5-(2-aminoethyl)aminocarbonyl-1-pentynyl, R³ and R⁴ are hydroxyl, and R⁵ is methylamino carbonyl, or a pharmaceutically acceptable salt thereof.
 17. The compound of claim 1, wherein R² is selected from the group consisting of carboxyalkylalkynyl, alkoxycarbonylalkylalkynyl, aminoalkylaminocarbonylalkyl alkynyl, amino (alkylene-NH—)_(n) alkylaminocarbonyl wherein n is 1 to 6, aminoalkylcarbonylaminoalkylaminocarbonyl, aminoalkylaminocarbonyl whose amino end is linked to a label, dye, or reporter group, amino (alkylene-NH—)_(n) alkylaminocarbonyl wherein n is 1 to 6 whose amino end is linked to a label, dye, or reporter group, aminoalkylcarbonylaminoalkylaminocarbonyl whose amino end is linked to a label, dye, or reporter group.
 18. The compound of claim 1, wherein R¹ is 3-chlorobenzyl, R² is selected from the group consisting of C≡C(CH₂)₂COOH, C≡C(CH₂)₄COOH, C≡C(CH₂)₂COOCH₃, C≡C(CH₂)₄COOCH₃, C≡C(CH₂)₂CONH(CH₂)₂NH₂, C≡C(CH₂)₄CONH(CH₂)₂NH₂, C≡C(CH₂)₂CONH(CH₂)₃NH₂, C≡C(CH₂)₂CONH(CH₂)₄NH₂, C≡C(CH₂)₂CO[NH(CH₂)₂]₂NH₂, C≡C(CH₂)₂CONH(CH₂)₂NH-biotin, and C≡C(CH₂)₂CONH(CH₂)₂NH—CO(CH₂)₅NH-biotin, and C≡C(CH₂)₂CONH(CH₂)₂NH—CO—(CH₂)₅Cy₅ wherein Cy₅ is a cyanine dye, R³ and R⁴ are hydroxyl, and R⁵ is methylamino carbonyl, or a pharmaceutically acceptable salt thereof.
 19. A compound of Formula II:

wherein: R⁶ is C₆-C₁₄ aryl C₁-C₆ alkyl wherein the C₆-C₁₄ aryl is substituted with a group represented by C≡C—(CH₂)_(n)—COR¹¹ wherein R¹¹ is selected from the group consisting of OH, OR¹², and NR¹³R¹⁴, wherein R¹² is selected from the group consisting of C₁-C₆ alkyl, C₃-C₈ cycloalkyl, C₃-C₈ cycloalkyl C₁-C₆ alkyl, C₃-C₈ dicycloalkyl C₁-C₆ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₆ alkyl, C₇-C₁₄ tricycloalkyl C₁-C₆ alkyl, C₆-C₁₄ aryl, C₆-C₁₄ aryl C₁-C₆ alkyl, C₆-C₁₄ and diaryl C₁-C₆ alkyl; R¹³ and R¹⁴ are independently selected from the group consisting of hydrogen, C₁-C₆ alkyl, and (CH₂)_(n)R¹⁵ wherein R¹⁵ is NR¹⁶R¹⁷, wherein R¹⁶ and R¹⁷ are independently selected from the group consisting of hydrogen, C₁-C₆ alkyl, and COR¹⁸ wherein R¹⁸ is hydrogen or C₁-C₆ alkyl; wherein n is an integer from 1 to 10; R⁷ is selected from the group consisting of bromo, chloro, iodo, C₁-C₂₀ alkyl, C₇-C₁₂ cycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkyl C₁-C₂₀ alkyl, C₇-C₁₂ bicycloalkenyl C₁-C₂₀ alkyl, C₆-C₁₄ aryl C₁-C₂₀ alkyl, C₂-C₂₀ alkenyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkenyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkenyl, C₆-C₁₄ aryl C₂-C₂₀ alkenyl, C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, and C₆-C₁₄ aryl C₂-C₂₀ alkynyl, and the alkyl, cycloalkyl, or aryl portion of R⁷ is optionally substituted with one or more substituents selected from the group consisting of halo, hydroxyl, amino, alkylamino, dialkylamino, mercapto, carboxy, alkoxycarbonyl, aminocarbonyl, alkylaminocarbonyl, dialkylaminocarbonyl, aminoalkylaminocarbonyl, trialkylsilyl, and any combination thereof; R⁸ and R⁹ are independently selected from the group consisting of hydroxyl, amino, mercapto, ureido, C₁-C₆ alkyl carbonylamino, hydroxy C₁-C₆ alkyl, and hydrazinyl; and R¹⁹ is selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl)aminocarbonyl, C₁-C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, hydrazinyl, amino C₁-C₃ alkyl, hydroxy C₁-C₃ alkyl, C₃-C₆ cycloalkylamino, hydroxylamino, and C₂-C₃ alkenyl; or a pharmaceutically acceptable salt thereof.
 20. The compound of claim 19, wherein R⁶ is benzyl substituted with C≡C—(CH₂)_(n)—COR¹¹, wherein R¹¹ is selected from the group consisting of OH, OR¹², and NR¹³R¹⁴, and wherein n is an integer of 1 to 10, or a pharmaceutically acceptable salt thereof.
 21. The compound of claim 20, wherein R¹¹ is OR¹² and wherein R¹² is C₁-C₆ alkyl, or a pharmaceutically acceptable salt thereof.
 22. The compound of claim 20, wherein R¹¹ is NR¹³R¹⁴ and wherein R¹³ and R¹⁴ are both hydrogen, or a pharmaceutically acceptable salt thereof.
 23. The compound of claim 20, wherein R¹¹ is NR¹³R¹⁴, wherein R¹³ is hydrogen, wherein R¹⁴ is (CH₂)_(n)R¹⁵, and wherein R¹⁵ is NR¹⁶R¹⁷, or a pharmaceutically acceptable salt thereof.
 24. The compound of claim 19, wherein R⁷ is selected from the group consisting of chloro, bromo, iodo, C₂-C₂₀ alkynyl, C₇-C₁₂ cycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkyl C₂-C₂₀ alkynyl, C₇-C₁₂ bicycloalkenyl C₂-C₂₀ alkynyl, and C₆-C₁₄ aryl C₂-C₂₀ alkynyl, or a pharmaceutically acceptable salt thereof.
 25. The compound of claim 19, wherein R⁸ and R⁹ are independently selected from the group consisting of hydroxyl, amino, mercapto, and ureido, or a pharmaceutically acceptable salt thereof.
 26. The compound of claim 19, wherein R¹⁰ is selected from the group consisting of C₁-C₃ alkyl aminocarbonyl, di(C₁-C₃ alkyl)aminocarbonyl, C₃ alkylthio C₁-C₃ alkyl, halo C₁-C₃ alkyl, amino C₁-C₃ alkyl, hydroxy C₁-C₃ alkyl, and C₃-C₆ cycloalkylamino, or a pharmaceutically acceptable salt thereof.
 27. The compound of claim 26, wherein R¹⁰ is C₁-C₃ alkyl aminocarbonyl or di(C₁-C₃ alkyl)aminocarbonyl, or a pharmaceutically acceptable salt thereof.
 28. The compound of claim 27, wherein R¹⁰ is methylaminocarbonyl, or a pharmaceutically acceptable salt thereof.
 29. The compound of claim 19, wherein R⁶ is 3-(5-carboxy-1-pentynyl)benzyl, 3-(5-(2-aminoethyl)aminocarbonyl-1-pentynyl)benzyl, or 3-(5-(2-acetamidoethyl)aminocarbonyl-1-pentynyl)benzyl, R⁷ is chloro, R⁸ and R⁹ are hydroxyl, and R¹⁰ is methylamino carbonyl, or a pharmaceutically acceptable salt thereof.
 30. A pharmaceutical composition comprising a compound of claim 1 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.
 31. A method for activating an A₃ adenosine receptor in a mammal comprising administering to the mammal an effective amount of a compound of claim 1 or a pharmaceutically acceptable salt thereof.
 32. A method for activating an A₃ adenosine receptor in a cell comprising contacting said cell with a compound of claim 1 or a pharmaceutically acceptable salt thereof.
 33. A method for activating A₃ adenosine receptors in a mammal comprising administering to the mammal an effective amount of a compound of claim 19 or a pharmaceutically acceptable salt thereof.
 34. A pharmaceutical composition comprising a compound of claim 19 or a pharmaceutically acceptable salt thereof and a pharmaceutically acceptable carrier.
 35. A method for activating an A₃ adenosine receptor in a mammal comprising administering to the mammal an effective amount of a compound of claim 19 or a pharmaceutically acceptable salt thereof. 